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Forecasting models for real estate market analysis The case study of Portugal

Coutinho, Ana Lúcia Barata

Abstract

The real estate market is known for its difficulties and volatility, particularly in determining property values, which significantly impact economic choices and societal well-being. Accurate predictions of property prices can facilitate informed decision-making and influence investment strategies and market dynamics. This study focuses on predicting property prices in Portugal and looks at different regions with a focus on Lisbon. It attempts to use innovative methods such as Decision Tree, Random Forest, Artificial Neural Networks, Linear Regression, and K-Nearest Neighbors. The research provides an in-depth evaluation of forecasting techniques by analyzing historical data and employing various machine learning algorithms. The models are specifically designed to understand the complex dynamics of different property types in different regions of Portugal. Overall, the Random Forest model is the best model for predicting property prices, followed by Decision Tree model. This forecast is also important because it provides us with an insight into the importance of certain features in real estate property prices. Using advanced predictive models does not only enhance the understanding of real estate market trends but also enables stakeholders to make informed decisions.

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Mas e Deg ee P og am in In o ma ion Managemen Fo ecas ing models o eal es a e ma ke analysis The case s udy o Po ugal Ana Lúcia Ba a a Cou inho P ojec Wo k p esen ed as pa ial equi emen o ob aining he Mas e Deg ee P og am in In o ma ion Managemen NOVA In o ma ion Managemen School Ins i u o Supe io de Es a ís ica e Ges ão de In o mação Uni e sidade No a de Lisboa MGI NOVA In o ma ion Managemen School Ins i u o Supe io de Es a ís ica e Ges ão de In o mação Uni e sidade No a de Lisboa FORECASTING MODELS FOR REAL ESTATE MARKET ANALYSIS THE CASE STUDY OF PORTUGAL By Ana Lúcia Ba a a Cou inho P ojec Wo k p esen ed as pa ial equi emen o ob aining he Mas e ’s deg ee in In o ma ion Managemen , wi h a specializa ion in Knowledge Managemen and Business In elligence Supe iso (s): João B uno Mo ais de Sousa Ja dim Miguel de Cas o Simões Fe ei a Ne o No embe 2023 ii STATEMENT OF INTEGRITY I he eby decla e ha ing conduc ed his academic wo k wi h in eg i y. I con i m ha I ha e no used plagia ism o any o m o undue use o in o ma ion o alsi ica ion o esul s along he p ocess leading o i s elabo a ion. I u he decla e ha I ha e ully acknowledge he Rules o Conduc and Code o Hono om he NOVA In o ma ion Managemen School. [Ana Lúcia Ba a a Cou inho] [Lisbon, No embe 22nd, 2023] iii ACKNOWLEDGEMENTS This esea ch would no ha e been possible wi hou he inc edible suppo o coun less people who guided me h ough he p ocess, sha ed hei knowledge and answe ed all o my ques ions. I would like o hank my amily o belie ing in me and i was because o hei emo ional suppo ha hey kep my mo i a ion high h oughou he p ojec . Thanks o my iends and da a scien is s who p o ided ad ice and eedback on he many challenges I had o o e come. I am especially hank ul o my wo co-supe iso s Miguel de Cas o Ne o and João B uno Ja dim and NOVA IMS o p o iding ma e ials and suppo in he essen ial con ex ha helped en ich my knowledge and his esea ch. i ABSTRACT The eal es a e ma ke is known o i s di icul ies and ola ili y, pa icula ly in de e mining p ope y alues, which signi ican ly impac economic choices and socie al well-being. Accu a e p edic ions o p ope y p ices can acili a e in o med decision-making and in luence in es men s a egies and ma ke dynamics. This s udy ocuses on p edic ing p ope y p ices in Po ugal and looks a di e en egions wi h a ocus on Lisbon. I a emp s o use inno a i e me hods such as Decision T ee, Random Fo es , A i icial Neu al Ne wo ks, Linea Reg ession, and K-Nea es Neighbo s. The esea ch p o ides an in-dep h e alua ion o o ecas ing echniques by analyzing his o ical da a and employing a ious machine lea ning algo i hms. The models a e speci ically designed o unde s and he complex dynamics o di e en p ope y ypes in di e en egions o Po ugal. O e all, he Random Fo es model is he bes model o p edic ing p ope y p ices, ollowed by Decision T ee model. This o ecas is also impo an because i p o ides us wi h an insigh in o he impo ance o ce ain ea u es in eal es a e p ope y p ices. Using ad anced p edic i e models does no only enhance he unde s anding o eal es a e ma ke ends bu also enables s akeholde s o make in o med decisions. KEYWORDS Real Es a e, Real Es a e P ope y P ices, Machine Lea ning, Random Fo es , A i icial Neu al Ne wo k, K-Nea es Neighbo s, Decision T ee. Sus ainable De elopmen Goals (SGD): The s udy is aligned wi h Sus ainable De elopmen Goal 9: Indus y, Inno a ion, and In as uc u e, employing inno a i e me hods such as Decision T ee, Random Fo es , A i icial Neu al Ne wo k, Linea Reg ession, and K-Nea es Neighbo s. Mo e speci ically, his hesis aims o p oduce knowledge o he echnological ad ancemen o he eal es a e ield, by in eg a ing eal es a e da a o unde s and and o ecas p ice dynamics. In such a complex and c ucial domain, his esea ch hus p o ides one mo e con ibu ion o unde s and he eal es a e p ope y ma ke p ices and add essing i s cu en challenges. INDEX 1. In oduc ion .................................................................................................................. 1 2. Li e a u e e iew .......................................................................................................... 3 2.1. Mac oeconomic ..................................................................................................... 3 2.1.1. Bubbles ........................................................................................................... 4 2.1.2. Tou ism ........................................................................................................... 5 2.1.3. C ime .............................................................................................................. 5 2.2. P ice Fo ecas ........................................................................................................ 6 2.2.1. Compa a i e analysis o p edic i e models ................................................... 8 3. Me hodology .............................................................................................................. 11 3.1. Da ase Desc ip ion and modi ica ions ............................................................... 11 3.2. Model E alua ion Me ics ................................................................................... 14 3.2.1. Da a Impu a ion o he missing alues ........................................................ 16 4. Resul s and discussion ................................................................................................ 19 4.1. Explo a o y analysis ............................................................................................. 19 4.1.1. Explo ing ela ionships among key a iables ............................................... 19 4.1.2. Explo ing p ice ends in geog aphic con ex .............................................. 25 4.2. Models composi ion ............................................................................................ 30 4.3. Model esul s ....................................................................................................... 31 4.3.1. E o analysis o machine lea ning models .................................................. 34 5. Conclusions and u u e wo ks .................................................................................... 42 Bibliog aphical Re e ences .............................................................................................. 44 i LIST OF FIGURES Figu e 1 - Diag am ha illus a es he p ocess ha was conduc ed in his s udy .................... 2 Figu e 2 - T end o a iables o e he yea s ............................................................................ 20 Figu e 3 – P esence o absence o p ope y commodi ies o e ime ...................................... 20 Figu e 4 - Pe cen age o p ope ies ha ha e he selec ed a iable. ..................................... 21 Figu e 5 – E olu ion o P ope y Condi ion and Ene gy E iciency Ce i ica e o e ime ........ 21 Figu e 6 - Numbe o newly cons uc ed p ope ies wi h speci ic cha ac e is ics .................. 22 Figu e 7 - Numbe o newly cons uc ed p ope ies as apa men o houses ........................ 22 Figu e 8 – P ope y commodi ies analysis by p ope y ype in Ru al and Non-Rual a eas ..... 23 Figu e 9 - Dis ibu ion o p ope ies along he egions ........................................................... 24 Figu e 10 - Rela ionship be ween GBA and Numbe o bed ooms ......................................... 25 Figu e 11 - E olu ion o eal es a e p ope y p ices ................................................................ 25 Figu e 12 - E olu ion o eal es a e p ope y p ices along he egions ................................... 26 Figu e 13 - A e age p ope y selling p ices along he egions................................................. 27 Figu e 14 - A e age p ope y selling p ices in he dis ic s o Po ugal ................................... 27 Figu e 15 - A e age p ope y selling p ices in municipali y o Lisbon ..................................... 28 Figu e 16 - A e age p ope y selling p ices in he pa ish o Cascais........................................ 29 Figu e 17 - A e age p ope y selling p ices in he pa ish o Lisbon ......................................... 29 Figu e 18 - Hea map o he e olu ion o p ope y selling p ices in Lisbon's pa ishes ............. 30 Figu e 19 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices using Random Fo es ................................................................................................................. 35 Figu e 20 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices using Decision T ee .................................................................................................................... 36 Figu e 21 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices using KNN .......................................................................................................................................... 36 Figu e 22 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices in Lisbon using Random Fo es ........................................................................................................ 37 Figu e 23 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices in Lisbon using Decision T ee .......................................................................................................... 37 Figu e 24 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices in No h using Random Fo es ........................................................................................................ 38 Figu e 25 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices in Cen e using Random Fo es ........................................................................................................ 38 Figu e 26 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices in Alen ejo using Random Fo es ........................................................................................................ 39 ii Figu e 27 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices in Alga e using Random Fo es ........................................................................................................ 39 Figu e 28 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices in Lisbon Apa men s using Random Fo es .................................................................................... 40 Figu e 29 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices in Lisbon Houses using Random Fo es ........................................................................................... 40 iii LIST OF TABLES Table 1 - Compa a i e analysis o p edic i e models .............................................................. 10 Table 2 - Va iables Desc ip ion ................................................................................................. 14 Table 3 - Explana ion o he me ics o ul ill missing alues ................................................... 15 Table 4 - Explana ion o he me ics selec ed o e alua ion o each o he models .............. 16 Table 5 - Explana ion o he ules applied................................................................................ 17 Table 6 - Resul s o he bes me hod o handle he missing alues ........................................ 18 Table 7 - Bes hype pa ame e s o he models ...................................................................... 31 Table 8 - Machine Lea ning Expe imen a ion o P ope y P ice P edic ion ........................... 34 6 whe he he e is a ela ionship be ween c ime a es and eal es a e p ices in Poland. The s udy led hem o conclude ha geog aphic a eas wi h lowe alues appea ed in a eas wi h highe c ime a es. They also examine he e ec s o gen i ica ion, a p ocess ha a ac s high-income households and businesses, esul ing in highe incomes and educa ion le els and lowe c ime a es among his popula ion. Thus, an inc ease in housing p ices is associa ed wi h a dec ease in c ime. “The decline in sa e y coincides wi h he de e io a ion o he li ing condi ions o he popula ion bu also educes us in he police and judicial sys em” (Fo yś & Pu ek-Szeląg, 2017, p. 52). C ime educes he demand o eal es a e in ha geog aphic a ea, which educes he a ea's popula i y and p ices. Buye s a e willing o pay mo e o li e in a eas wi h lowe c ime a es so hey can enjoy g ea e sa e y and a be e quali y o li e (Buonanno e al., 2013). 2.2. PRICE FORECAST The e a e many s udies ha use di e en o ecas ing me hods. We will analyze some o hem and hei esul s o de e mine he bes me hod. Some s udies a e done using mic o a iables, as in ou case. Va iables such as numbe o bed ooms, numbe o ba h ooms, size o he house, whe he i has a ga age, a balcony, o e en a swimming pool a e included in his analysis. Fu he mo e, eal es a e p ope y p ices a e a ec ed by many cha ac e is ics, some o which a e ela ed o he cha ac e is ics o a speci ic home. The mos common a iables o he model s udied by (Wing & Chin, 2003) include a ibu es such as ype, age o he building, numbe o bed ooms and ba h ooms, acili ies (e.g. swimming pool), ga age, pa io, g oss a ea, and building se ices (e.g., ai condi ional, li , e c). The applica ion o hedonic p ice o eal es a e ma ke s iden i ies a se o key a iables o be included in he model, showing ha he e ec s o one o mo e eal es a e a ibu es on eal es a e p ices can be obse ed, while o he ac o s being cons an . (Fle che e al., 2000) conduc ed a s udy wi h he aim o de e mining he lis o a iables o be included in a hedonic p icing model and ound ha , he numbe o bed ooms, ba h ooms and g oss a ea can be posi i ely ela ed o i s p ice. In he esea ch o (My-Linh, 2020) e ealed ha he age o he building can impac p ope y eal es a e p ices nega i ely. To es ima e p ope y p ices (Pai & Wang, 2020) also included a iables such as dis ance o he ci y cen e and p oximi y o he subway in his p edic ions, and used many me hods (Decision T ee, Back P opaga ion Neu al Ne wo ks, Gene al Reg ession Neu al Ne wo ks and Leas Squa es Vec o Reg ession) o p edic p ope y p ices. They conclude ha i is possible o p edic he p ices using hese me hods and ha he me hod ha mos accu a ely e lec s eal es a e p ope y p ices is leas squa es ec o eg ession. (Liu, 2022) esea ch analyses he eal es a e ma ke applying Mul iple Linea Reg ession Model, he s udy shows a s ong co ela ion be ween he income le els wi h eal es a e p ices e sus, he models demons a e a high accu acy wi h lowe p edic ion e o , indica ing i s p ac icali y in o ecas ing eal es a e ma ke ends. Random Fo es is a decision ee-based ensemble model ha uses a echnique called boo s ap agg ega ion (o bagging) o c ea e mul iple independen eg ession models om andom samples o he aining da a se . I is a e sa ile me hod ha can handle bo h eg ession and classi ica ion asks. The main p ocess in ol es building a ious decision ees by andomly selec ing da a poin s and 7 ea u es du ing aining, which ul ima ely helps imp o e model accu acy (Ja’a a e al., 2021). In a compa a i e s udy by (Čeh e al., 2018), he Random Fo es model was compa ed wi h Linea Reg ession o p edic eal es a e p ices. The esul s show ha Random Fo es consis en ly pe o med be e han Linea Reg ession model on a a ie y o pe o mance me ics. Fu he mo e, Random Fo es ha e lowe e o a es in p edic ing eal es a e p ices compa ed o o he algo i hms (Shinde & Gawande, 2018). In a s udy conduc ed by (del Cacho, 2010), a ious models such as Naï e Neighbo s, Linea Reg ession, Decision T ees, K-Nea es Neighbo s (KNN) and Neu al Ne wo ks we e used o p edic eal es a e p ices. A poin o highligh ela ed o his s udy is he ac ha Naï e Neighbo s is a classi ie ha assumes ha all a iables a e independen o each o he . The esul s we e e alua ed based on a ious indica o s and i was ound ha he Decision T ee model p o ided he bes indica o pe o mance in e ms o eal es a e p ices. A i icial Neu al Ne wo k (ANN) ha e a wide ange o uses, o ecas ing is one o he pu poses so many esea che s decided o apply his echnique. I is able o add ess p oblems ela ed o nonlinea i y and mul icollinea i y. One o he ad an ages o his model is i s e sa ili y, i has he abili y o model ela ionships be ween dependen and independen a iables. (Ghodsi e al., 2010) in hei esea ch o es ima ion o I anian house p ices, in o de o o m an A i icial Neu al Ne wo king, conside ed economic a iables including, he housing p ice index, GDP, and cos o cons uc ion ma e ials, he esul was a success ul es ima ion o he p ices o he a iables. (Tabales e al., 2013) did o ecas ing o he eal es a e ma ke and show ha ANN has be e p e ision esul s han econome ic models. The s udy conduc ed by (Rahman e al., 2019) also using ANN o o ecas housing p ices, concluded ha ANN has he po en ial o o ecas house p ices wi h high pe o mance and also con i med he indings made by (Tabales e al., 2013), he ANN model achie ed be e esul s when es ed in a la ge da ase . (Bahia, 2013) used wo ypes o ANN: Feed Fo wa d Back P opaga ion Neu al Ne wo k (FFBP) and Cascade Fo wa d Back P opaga ion Neu al Ne wo k (CFBP) o p edic eal es a e p ices. The di e ence be ween hese wo ypes is ha he second me hod, CFBP, includes a weigh ed connec ion om he inpu o each laye and successi e laye s. The conclusion o his esea ch is ha he CFBP me hod shows esul s ha a e closes o eal p ices since i is possible o adjus he weigh s, he esul s we e mo e accu a e, his s udy achie ed mo e han 96% accu acy in p edic ing eal es a e p ices. O he me hods a e also used by mo e esea che s, such as Mul iple Linea Reg ession, which we ha e p e iously alida ed (G um & Go eka , 2016) o see he ela ionship be ween house p ices and mac oeconomic a iables in di e en egions and cul u es (G eece, Poland, e c.), and i u ns ou ha he e is a s ong ela ionship be ween he a iables s udied, namely he unemploymen a e and house p ices, which accu a ely illus a es he mac oeconomic impac on his ma ke . Using mac oeconomic a iables, GDP, house p ice index, consume index, (Li & Chu, 2017) and wi h he o ecas ing me hods Back P opaga ion and ANN, i is concluded ha hese a iables a e no s ong enough o p edic house p ices. Based on he inal p ice o se e al houses o e 4 yea s, (Singh e al., 2020) used h ee di e en me hods: Random Fo es , G adien Boos ing and Linea Reg ession, in o de o p edic house p ices, he conclusion is ha all o ecas ing models we e able o p edic p ices bu he model wi h highe o ecas ing accu acy was he G adien Boos ing. One p oblem ha mos o he p e ious s udies ha e is he ac ha hey don’ ake in o accoun he economic si ua ion o e ime, so, hei s udies need o be upda ed equen ly o he wise hey became 8 ou da ed. (Yasni sky e al., 2021) saw his as an oppo uni y and de eloped a mass alua ion o eal es a e in Russia based on ixed ac o s, loca ion, and a iable ac o s, economic pa ame e s. The esul o he model elabo a ed was ha houses in di e en geog aphical loca ions eac di e en ly o he economic changes whe e hey a e inse ed, he olume o loans, and he GDP o he coun y. This model is e y di e en in ha i can easily adap o he economy and he cons an changes ha exis . (Hishamuddin e al., 2020) saw ha no many s udies combine mic oeconomic and mac oeconomic a iables, so hey decided o conside bo h in hei pape o ha e a ision in a sho and long e m o p ope y p ices, he me hod chosen was ANN. Using R² in e o measu emen as a basis, hey conclude ha he pe cen age o e o is less when R² has a high alue when only mac oeconomic a iables we e conside ed. When only mic oeconomic a iables we e used alone he esul s we e eally weak, and when bo h a iables we e combined, he esul s we e be e han using mic oeconomic a iables alone bu wo se han using mac oeconomics a iables alone. The e o e, i is necessa y o s udy his combina ion o a iables in mo e de ail o a oid alue disc epancies and o ob ain a mo e eliable p ice p edic ion. Wi h his s udy, i is possible o see ha he e is a gap in esea ch and an oppo uni y o explo e he combina ion o hese wo mac o a iables. We need o conside bo h he mic o a iables desc ibed abo e and he mac oeconomic a iables such as in la ion, unemploymen a e, in e es a e, e c. 2.2.1. Compa a i e analysis o p edic i e models The eal es a e ma ke is in luenced by se e al quan i a i e and quali a i e a iables, making p ice o ecas ing a complex ask. To add ess his challenge, a ious p edic i e models ha e been used o ill in he null alues ha we ha e in he da a and o es ima e eal es a e p ices. This esea ch aims o examine and compa e se e al p edic i e models, including A i icial Neu al Ne wo k (ANN), Linea Reg ession, Decision T ees, K-Nea es Neighbo Impu a ion (KNN), Random Fo es , and G adien Boos ing. Each o hese models has unique s eng hs and limi a ions ha make i sui able o di e en scena ios. By e alua ing and compa ing hese models agains each o he , we aim o p o ide aluable insigh s in o hei pe o mance and e ec i eness. Table 1 lis s a ious o ecas ing models, each wi h a b ie desc ip ion, s eng hs, and limi a ions. Among he au ho s who s udied p edic i e models, hose who a e men ioned a e pa o he esea ch ca ied ou ha ga e ise o he able. P edic i e Model Desc ip ion and De ini ion S eng hs Limi a ions ANN (Hush & Ho ne, 1993) I 's a ype o Neu al Ne wo k algo i hm ha consis s o in e connec ed nodes o neu ons o ganized in o laye s, usually including inpu , hidden, and ou pu laye s. These ne wo ks ake inpu da a and p edic an ou pu based on i . Du ing aining, neu al ne wo ks adjus he connec ions' weigh s o lea n • Capable o handling non- linea and complex da a. • Sui able o big da a applica ions due o hei abili y o model in ica e ela ionships. • Requi es a la ge aining da ase o op imal pe o mance. • P one o o e i ing i no ca e ully egula ized. 9 complex pa e ns and make p edic ions. Linea Reg ession (Mon gome y e al., 2021) Is a s a is ical model ha es ablishes a linea ela ionship be ween p edic o a iables and he a ge a iable. I assumes a linea combina ion o ea u es and inds coe icien s ha minimize he e o be ween p edic ed and ac ual alues. • Simple and easy o in e p e , making i a good choice o ini ial insigh s. • Wide applicabili y o a ex end o p oblems. • Me hod limi ed o linea ela ionships be ween a iables, which may no cap u e complex pa e ns. • Sensi i e o ou lie s and mul icollinea i y. Decision T ees (de Ville, 2013) A e cons uc ed by algo i hms ha explo e di e en ways o spli ing he da a in o dis inc segmen s. They make decisions based on ea u e spli s, c ea ing a ee whe e each node ep esen s a decision. The ee is spli based on he ea u e ha p o ides he bes in o ma ion gain. • Easily in e p e able models, as hey mimic human decision-making p ocesses. • Can handle bo h nume ical and ca ego ical da a. • Tendency o o e i wi h deep ees, which equi es p uning o ensemble me hods. • Sensi i e o small a ia ions in he aining da a. KNN (Weinbe ge & Saul, 2009) KNN is a non-pa ame ic algo i hm ha p edic s a a ge a iable based on he majo i y class o i s k-nea es neighbo s in a ea u e space. I de e mines he a ge alue by conside ing he labels o hese neighbo s. P edic ion wi h KNN equi es de ine he chosen a iables, he dis ance me ic o calcula e he dis ance be ween obse a ions and he numbe o neighbo s. • Abili y o adap o complex da a pa e ns, especially when he numbe o neighbo s (k) is app op ia ely chosen. • Pe o ms well on small da ase s and wi h ew ea u es. • Sensi i e o he choice o 'k', which can signi ican ly a ec esul s. • Is in luenced by ou lie s in he da a, leading o inaccu a e p edic ions. Random Fo es (Oshi o e al., 2012) Random Fo es is an ensemble me hod ha combines se e al Decision T ees. This model is pa icula ly known o i s abili y o e ec i ely handle a la ge numbe o ea u es and • Reduces o e i ing h ough ensemble a e aging. - Handles missing da a e ec i ely • The ela ionship be ween he esponse and he independen a ibu es is 10 e icien ly p ocess ex ensi e da ase s. Also imp o es p edic ion accu acy and educe o e i ing by agg ega ing p edic ion om mul iple decision ees. wi hou p ep ocessing. complica ed o unde s and. • Tend o ha e longe aining imes compa ed o o he me hods, so is less sui able o eal- ime applica ions o e y la ge da ase s. G adien Boos ing (Has ie e al., 2009) Is a me hod ha sequen ially cons uc s an ensemble o weak lea ne s (usually decision ees) o c ea e a s ong p edic i e model. I builds ees sequen ially, ocusing on he mis akes made by p e ious ees. This me hod gained popula i y due o he supe io pe o mance o Decision T ees and led o he de elopmen o algo i hms such as XGBoos and Ligh GBM. • High accu acy and e ec i eness ac oss many scena ios. • Handles missing da a e ec i ely. • Can be sensi i e o ou lie s in he aining da a. • P one o o e i ing, especially when he algo i hm is allowed o c ea e complex models. Table 1 - Compa a i e analysis o p edic i e models 11 3. METHODOLOGY The objec i e o his s udy is o build a p ope y p ice o ecas ing model using p edic i e models. P ope y p ice o ecas s a e designed o help homebuye s unde s and u u e p ice anges and plan hei inances in ad ance. In addi ion, p ope y p ice o ecas s a e also bene icial o eal es a e in es o s o unde s and he end o p ope y p ices in a pa icula egion. This s udy e e s o Po ugal Con inen al and was a ocus on Lisbon since Lisbon is he capi al o Po ugal. Lisbon is whe e he e a e mo e da a and exis a la ge di e ence in p ice a ia ion and whe e he di e ences be ween cul u es, ends and li es yles a e mos p onounced, whe e is a lo o business ac i i y and ou ism, he e o e his allows o a comp ehensi e analysis wi h abundan da a. To make accu a e o ecas s, we need sui able ma hema ical models o es ima e how ime se ies da a gene a e house p ices. In his con ex , CRISP-DM me hod was adap ed o his si ua ion, as discussed by (Shea e , 2020). Analyzing cu en ends and p edic ing u u e ends is becoming inc easingly impo an oday. P edic i e models a e gaining inc easing alue in o ganiza ions ha ace he challenge o choosing he igh echnology o he business and unde s anding how o use exis ing da a (Nwagwu e al., 2021). The eal es a e ma ke is known o i s ola ili y, cha ac e ized by luc ua ions o e ime and con inually changing ends. Gi en he complexi y o he eal es a e ma ke , which o en exhibi s non- linea ela ionships, i becomes necessa y o le e age his o ical da a and employ machine lea ning me hods o analysis (Han, 2018). Machine lea ning o e s he ad an age o au oma ically lea ning pa e ns and insigh s om his o ical da a, making i well sui ed o handling he di icul ies o he eal es a e ma ke . Fo he cons uc ion o he p edic ion model, he p og amming language selec ed was Py hon. I is he mos used language wo ldwide occupying he i s place in Oc obe 2023 1 , and is a use - iendly in e ace as i is easy o unde s and and has a wide a ie y o lib a ies a ailable, which helps o inc ease o hose uses his language sa ing p og amming ime ha would be manual. In line o ensu e ha he in o ma ion is accu a e in his con ex , he da a we e subjec o ea men and ules we e de ined. Be o e s a ing o de elop he model, i is necessa y o p ocess da a ha in ol es impo ing iles in CSV o ma , Explo a ion and Da a Unde s anding, Da a P e-p ocessing, Fea u e Selec ion, Modelling and Pe o mance Assessmen . 3.1. DATASET DESCRIPTION AND MODIFICATIONS The s udy began by impo ing da a om wo Excel iles in o Jupy e . One o hese iles con ained he yea o cons uc ion o he p ope ies, while he o he ile held a wide ange o a iables ha cons i u e he da ase , such as he ype o p ope y (house o apa men ), numbe o bed ooms, ene gy e iciency ce i ica e, g oss building a ea, p ope y’s condi ion, he p esence o ga age, swimming pool, e ace and pa io, con ained as well a iables geog aphic ela ed, such as pa ish numbe , pos al code, la i ude and longi ude, and las ly in o ma ion linked o eal es a e ma ke p ices, he las ma ke appea ance da e and he selling p ice obse ed. To e i y i a p ope y had mul iple alues in he cons uc ion yea a iable, inconsis encies we e checked, and each p ope y ID was assigned a unique cons uc ion yea . 1 TIOBE Index - TIOBE 12 A me ge ope a ion was conduc ed be ween wo Excel iles o c ea e a uni ied da ase . The da a o his s udy consis ed o p ope ies up o he cons uc ion yea o 2024 and he e a e his o ical p ice sales be ween 2017 and 2022. Geog aphical in o ma ion, such as pa ish numbe and pos al code, allowed o he augmen a ion o he da ase wi h addi ional in o ma ion. This da a was de i ed om wo ex e nal iles 2 . The ollowing columns we e added: dis ic , zone, municipali y, and pa ish name, along wi h he u al/non- u al designa ion. Va ious ans o ma ions we e applied o hese new a iables o make hem usable. The p ope ies ha e been classi ied in o zones and u al and non- u al acco ding o he municipali ies, he e a e i e zones co e ing he da ase and Po ugal, he di ision is done acco ding o he cha ac e is ics o he zones and municipali ies, so we will ha e p ope ies in he same zone mo e simila o each o he 2. Two speci ic a iables ha had no signi ican alue o he da ase and only added complexi y we e emo ed, such as la i ude and longi ude, as hei in o ma ion was ound o be edundan since hey p o ided in o ma ion ha could be de i ed om he pos al code a iable. La i ude and longi ude ep esen geog aphic coo dina es and a e use ul when wo king wi h map o geocoding se ices. Howe e , in his case, he la i ude and longi ude do no change o he same pos al code, which is ac ually inco ec , so we conside emo ing hese wo a iables and keeping he da ase concise. Rega ding he yea o cons uc ion, he da ase compila ion e ealed se e al inconsis encies and nonsensical yea s, including he yea 1050. As a co ec i e app oach, all p ope ies wi h a cons uc ion yea p io o 1755 we e emo ed om he da ase . This decision was in luenced by his o ical e en s, no ably he de as a ing ea hquake ha s uck Lisbon in 1755, leading o widesp ead des uc ion by sunami and i e. Gi en he se e i y o he damage, i was assumed ha none o he houses cons uc ed be o e ha yea emained habi able. Consequen ly, hese p ope ies we e excluded om he analysis. The emo al o houses cons uc ed be o e 1755 and he handling o inconsis encies, such as he yea 1050, ensu ed da a quali y and eliabili y in he subsequen analysis. Se e al ans o ma ions and modi ica ions we e made o simply he da a. S a by ans o ming he p ope y ID a iable in o nume ical o ma o acili a e u he ans o ma ions. The p ope y condi ion a iable was ans o med in o nume ical alues anging om 1 o 4. The u al a iable was con e ed in o a bina y o ma , wi h 0 indica ing a u al loca ion and 1 ep esen ing a non- u al loca ion. Fu he analysis e ealed ha he EEC (Ene gy E iciency Ce i ica e) a iable could ake on nine dis inc le e s ha signi ican ly di e en EEC le els. To simpli y his a iable, i was g ouped in o ou dis inc classes: Class 1 includes ce i ica es A and A+, Class 2 encompasses ce i ica es B and B-, Class 3 consis s o ce i ica es C and D, and Class 4 comp ises he emaining ce i ica es E, F, and G. The modi ied da ase consis s o 326537 ows ep esen ing he numbe o p ope ies and includes 26 a iables ha will acili a e house p ice p edic ion modeling. Below, in able 2, is p esen ed all he 26 a iables selec ed a iables om he modi ied da ase , which will enable us o build he mos accu a e p edic i e model. Is also p esen he wo ex a a iables du ing he o ecas . 2 h ps://www.gpp.p /images/Es a is icas_e_analises/Es a is icas/associadasmedidasapoio/Te i o ios_Ru ais.pd h p://www.p ode .p /Resou cesUse /Documen os_Di e sos/33/PDRc_F eg_ZRu ais_NUTIIs_ e 2_co igido.pd 13 Va iable Desc ip ion Da a Type P ope y ID The unique iden i ie o he p ope ies Objec P ope y Type P ope y ype. 1 i is an apa men and 2 o a house In ege Nº Bed ooms Numbe o bed ooms In ege EEC Ene gy E iciency Ce i ica e: Numbe 1 includes ce i ica es A and A+, Numbe 2 ce i ica es B and B-, Numbe 3 consis s o ce i ica es C and D, and Numbe 4 comp ises he emaining ce i ica es E, F, and G. In ege GBA G oss Building A ea In ege Pa ish Pa ish Objec Pos al Code Pos al Code Objec Ga age Indica es whe he he p ope y has a ga age o no Bool Te ace Indica es whe he he p ope y has a e ace o no Bool Pool Indica es whe he he p ope y has a swimming pool o no Bool Pa io Indica es whe he he p ope y has a pa io o no Bool P ope y Condi ion The s a e o conse a ion o he house. I can be classi ied as good, bad, new, o used. Fo each s a e was assigned a numbe In ege Conse a ion S a e Ve i ied Indica es i he conse a ion s a e was p o ided by clien s o e i ied wi h pho os Bool Las Day in Ma ke Da e o he las ma ke upda e Da e ime Ini ial O e Da e Da e o he ini ial o e Da e ime Obse ed Selling P ice The selling p ices ha we e obse ed by he company In ege Cons uc ion Yea Yea o cons uc ion In ege 14 Dis ic Dis ic Objec Region Indica es one o he i e egions in o which Po ugal was di ided (No h, Cen e , Lisbon, Alen ejo and Alga e) Objec Municipali y Municipali y Objec Pa ish Name Name o he pa ish Objec Las Ma ke Upda e Yea Yea o he las ma ke upda e In ege Ini ial O e Yea Yea o he ini ial o e In ege Ru al Indica es whe he he p ope y is loca ed in a u al a ea o no Bool Decade Decade o cons uc ion (e.g., 50’s) Objec Cen u y Cen u y o cons uc ion (e.g., 20) In ege P edic ed Selling P ice The selling p ices ha we e p edic ed by he di e en models Floa Squa e me e P ice Di e ence P ice pe squa e me e . Di e ence be ween obse ed and p edic ed p ices Floa Table 2 - Va iables Desc ip ion Since his da ase con ains six a iables wi h a lo o missing alues, u he ans o ma ions we e pe o med o impu e he da a, conside ing he co ela ion be ween he a iables. Based on li e a u e e iew, he ollowing models we e selec ed: Decision T ee Impu a ion, Random Fo es Impu a ion, K- Nea es Neighbo Impu a ion (KNN), A i icial Neu al Ne wo k Impu a ion (ANN), and Linea Reg ession Impu a ion. The model chosen o each a iable was he one ha ga e he bes esul s compa ed o all he models s udied, in e ms o pe o mance me ics ( u he explained in he nex sec ion 3.2). 3.2. MODEL EVALUATION METRICS In his p ojec , a a ie y o e alua ion me ics ha e been employed o assess he pe o mance o di e en models, bo h in illing missing alues and p edic ing p ope y p ices. These me ics se e as essen ial ools o gauge he e ec i eness o he models. To e alua e he pe o mance o da a impu a ion models, we ocus on he me ics p esen ed in able 3, based on he classi ica ion esul s. 15 Me ic De ini ion In e p e a ion o he esul P ecision Measu es he p opo ion o co ec ly impu ed alues ( ue posi i es) ou o he o al impu ed alues. A high p ecision sco e indica es ha he me hod is adep a accu a ely illing in missing da a. Recall Quan i ies he a io o co ec ly impu ed alues ( ue posi i es) o he o al ac ual missing alues. A highe ecall sco e implies ha he me hod e ec i ely cap u es missing da a. F1-Sco e The F1-sco e s ikes a balance be ween p ecision and ecall, o e ing a single me ic o assess o e all pe o mance. I combines bo h p ecision and ecall in o a uni ied sco e, making i aluable o assessing he o e all quali y o da a impu a ion. A highe F1-Sco e indica es a be e balance be ween p ecision and ecall, meaning a be e pe o mance p edic ing missing alues. Suppo Rep esen s he numbe o ins ances o each class, e lec ing he dis ibu ion o missing da a poin s ac oss di e en ca ego ies. A highe suppo indica es ha he model’s p edic ions a e mo e eliable and us wo hy in impu e missing alues. Table 3 - Explana ion o he me ics o ul ill missing alues These me ics a e undamen al o e alua ing he pe o mance o da a impu a ion models in accu a ely illing missing alues. Addi ionally, hey guide us in choosing he mos e ec i e app oach o ensu e he eliabili y and comple eness o ou da ase , which, in u n, con ibu es o mo e accu a e p edic ions o house p ices. Fo he p edic ion o p ope y p ices, i is impo an o e alua e he pe o mance o each model de eloped using di e en me hods. The emphasis lies on six me ics: Accu acy, Mean Absolu e E o (MAE), Mean Squa e E o (MSE), Roo Mean Squa e E o (RMSE), Mean Absolu e Pe cen age E o (MAPE) and R² Sco e. Be o e using hese i e e alua ion indica o s, i is necessa y o unde s and hei meanings and conside hei in e p e a ion wi hin he speci ic con ex o his p ojec . In able 4 is ep esen ed an explana ion o he me ics o e alua e each o he models. Me ic De ini ion In e p e a ion o he esul Accu acy Measu es he p opo ion o co ec ly classi ied obse a ions ela i e o he o al. The highe he pe cen age, he be e he pe o mance o he model. MAE Measu es he di e ence be ween wo con inuous a iables, ansla ed in o he a e age o he e o s o a se o o ecas s. A lowe alue indica es ha he models is capable o p edic wi h accu acy he alues. 22 As we obse e an inc ease in he numbe o newly cons uc ed p ope ies, i is impo an o analyze he signi icance o p ope y commodi ies in hese new houses. F om Figu e 6, we can conclude ha new p ope ies end o exhibi hese cha ac e is ics mo e no ably. Ga age a iable appea in mo e han hal o new cons uc ions, p o iding in o ma ion abou which builde s and buye s a e inc easingly aluing. In he Figu e 7, we can also see he di e ence be ween he numbe o p ope ies being buil as apa men s e sus he numbe o homes, wi h mo e apa men s being cons uc ed. Figu e 6 - Numbe o newly cons uc ed p ope ies wi h speci ic cha ac e is ics Figu e 7 - Numbe o newly cons uc ed p ope ies as apa men o houses 23 To examine he geog aphic ela ionship be ween p ope ies in u al o non- u al a eas, analyzes we e conduc ed o assess he beha io o p ope y commodi ies in ela ion o he p ope y ypes. In Figu e 8, he di e ence be ween he pe cen age o he numbe o p ope ies wi h and wi hou hese o p ope y commodi ies a e no subs an ial. The mos no able di e ence can be obse ed in he p ope y ype, apa men , o a house. The e a e mo e apa men s in non- u al a eas compa ed o u al a eas, whe eas in u al a eas, he e is a highe p e alence o houses. The eason o his dis inc ion can be a ibu ed o u baniza ion ends, whe e non- u al a eas o en wi ness highe popula ion densi ies, leading o a g ea e demand o apa men s. Con e sely, u al a eas end o ha e mo e space a ailable, which encou ages home cons uc ion. Figu e 8 – P ope y commodi ies analysis by p ope y ype in Ru al and Non-Rual a eas Following he geog aphical analysis o p ope y cha ac e is ics, a ho ough s udy o p ope y commodi ies and p ope y ypes was ca ied ou o unde s and hei dis ibu ion ac oss he i e zones in Po ugal, as shown in Figu e 9. The ga age a iable displayed a consis en pe cen age h oughou he coun y, wi h he absence o ga ages being mo e common. 24 Rema kably, he swimming pool a iable s ood ou in he Alga e egion, whe e app oxima ely 10.73% o p ope ies ea u ed his a iable. In he sou he nmos egions o coun y, such as Alen ejo and Alga e, he p esence o e ace and pa io was signi ican ly mo e common. The Lisbon egion has a lowe p opo ion o p ope ies classi ied as Houses, while he zones Cen e and Alen ejo ha e a mo e balanced a io be ween apa men s and houses. I is no able ha he majo i y o p ope ies in he Alen ejo a e conside ed Ru al, making i he p edominan ly u al a ea in he coun y. Figu e 9 - Dis ibu ion o p ope ies along he egions 25 Figu e 10 illus a es he exis ence o a mode a ely s ong posi i e ela ionship be ween he a iables G oos Building A ea and he numbe o bed ooms. The co ela ion coe icien is 0.68, which is a ela i ely high ela ionship, indica ing a clea end whe e an inc ease in he g oss p i a e a ea o p ope ies co esponds o an inc ease in he numbe o ooms. Figu e 10 - Rela ionship be ween GBA and Numbe o bed ooms 4.1.2. Explo ing p ice ends in geog aphic con ex Con inuing he analysis o eal es a e p ope y p ices and examine hei de elopmen in di e en con ex s. Figu e 11 p o ides an insigh in o he a e age de elopmen o p ope y p ices in he yea s conside ed. I is e iden ha he p ices in 2018, he e was a signi ican ly inc ease compa ed wi h he p e ious yea . Th oughou he yea s 2018 o 2020, he e we e no subs an ial luc ua ions, and om he yea 2020 onwa ds, p ices ha e consis en ly been on he ise. Figu e 11 - E olu ion o eal es a e p ope y p ices 26 In Figu e 12, he p og ession o p ope y p ices ac oss he i e egions and he s udy yea s is ep esen ed. The No h egion exhibi s a g adual and less p onounced g ow h, while he Alga e egion expe iences sligh p ice luc ua ions. The Cen e and Alen ejo zones ha e main ained hei alues. In con as , he Lisbon egion boas s he highes eal es a e p ices p ices and displays a mo e signi ican p ice a ia ion, pa icula ly ma ked by p ice inc eases. Figu e 12 - E olu ion o eal es a e p ope y p ices along he egions 27 In o de o o ganize he zones om he highes a e age selling p ices o he lowes , he Figu e 13 is p esen ed. I is e iden ha Lisbon egion has he highes eal es a e p ices, closely ollowed by he Alga e egion. The Cen e egion is cha ac e ized by mo e a o dable p ope y p ices. Figu e 13 - A e age p ope y selling p ices along he egions I is impo an o ha e a sense o he p ice dispa i ies among he dis ic s o Po ugal. Con i ming he p e ious in o ma ion, Figu e 14, illus a es ha he Lisbon dis ic has he highes a e age p ope y p ices, closely ollowed by he Fa o dis ic . In con as , he Gua da dis ic eme ges as he mos budge - iendly op ion. Rema kably, he a e age housing p ice in Lisbon is o e h ee imes highe han ha in Gua da. In e ms o p icing wi hin his ma ke , Lisbon is 37% mo e expensi e han he second mos populous dis ic in he coun y, which is Po o. Figu e 14 - A e age p ope y selling p ices in he dis ic s o Po ugal 28 Gi en ha Lisbon is he dis ic wi h he highes eal es a e p ope y p ices, i becomes impo an o na ow down he geog aphical analysis. Consequen ly, he Lisbon municipali y was examined, and Figu e 15 appea s. Among he municipali ies wi hin he dis ic , Cascais s ands ou wi h he highes a e age housing p ices, closely ollowed by he Lisbon municipali y, wi h li le di e ence be ween he wo alues. In con as , Azambuja, a municipali y in he Lisbon dis ic , has he lowes a e age housing p ices, wi h a alue ha is o e h ee imes cheape compa ed o Cascais. Figu e 15 - A e age p ope y selling p ices in municipali y o Lisbon Since Cascais and Lisbon we e he municipali ies wi h he highes eal es a e selling p ices, Figu es 16 and 17 ep esen he p ices wi hin he espec i e pa ishes. In Cascais, he di e ence be ween he pa ish wi h he highes and he lowes p ices is app oxima ely he double. In Lisbon, he di e ences a e e en g ea e , wi h p ices a ying by almos ou imes om he pa ish wi h he highes a e age p ices o he one wi h he lowes . 29 Figu e 16 - A e age p ope y selling p ices in he pa ish o Cascais Figu e 17 - A e age p ope y selling p ices in he pa ish o Lisbon 30 As we can see, eal es a e p ope y p ices in Lisbon a e highe and he di e ences be ween pa ishes a e e y no iceable. To be e unde s and how p ices de elop in his pa ish, he as shown in Figu e 18 we e c ea ed. I is possible o examine he p ice e olu ion and maximum p ice spikes in each pa ish o Lisbon. In he yea 2017, p ope ies wi h he highes p ices we e loca ed in he San a Ma ia Maio and San o An ónio pa ishes. In 2018, he A enidas No as pa ish expe ienced a signi ican p ice inc ease, becoming he pa ish wi h he highes eal es a e p ope y p ices. In 2019, he Pa que das Nações pa ish doubled in alue compa ed o 2017, now anking among he pa ishes wi h he highes housing p ices, consis en ly inc easing in p ice o e he yea s. By 2022, we can conclude ha he op i e pa ishes wi h he highes p ope y p ices, in descending o de , a e A enidas No as, Pa que das Nações, San o An ónio, Belém, and Campolide. The pa ishes wi h lowe p ices ha ha e emained compa a i ely mo e a o dable include Ajuda, San a Cla a, Bea o, Penha da F ança, and Ma ila. Figu e 18 - Hea map o he e olu ion o p ope y selling p ices in Lisbon's pa ishes 4.2. MODELS COMPOSITION The inal da ase ep esen s a culmina ion o he bes models p e iously es ed o ul ill missing alues. Wi h hese e ined a iables now in eg a ed, he da ase s ands p epa ed o he accu a e p edic ion o p ope y p ices. Nex , we pe o m a igo ous compa ison o models o disce n hei e ec i eness in he eal es a e con ex . Th ough sys ema ic e alua ion and ca e ul analysis based on he p e iously men ioned me ics, we aim o iden i y he model ha pe o ms bes o he eal es a e p ice o ecas ing ask and he exis ing di e ences when analyzed in di e en geog aphic con ex . 31 Fo all he p edic ing me hods, he da ase was di ided in o wo se s, he aining se , and he es se . The o iginal da ase was also spli in o independen and dependen a iables, as his spli is essen ial o e alua ing model pe o mance using p e iously unseen da a. The spli be ween aining and es ing da ase was explo ed o he di e en scena ios. The spli used was 80% - 20%, which means 20% o he da a is used o he es ing da ase and he emaining 80% o he da a in he aining. A e aining, p edic ions we e made on he es basis. These o ecas s ep esen es ima es o he dependen a iable based on he independen a iable. In all models, he analysis o ea u e impo ance was conduc ed, and hese ea u es we e ca e ully chosen o c ea e he o ecas ing inpu s. The main ocus is o include ea u es ha ha e a s ong co ela ion wi h he a ge a iable and show a signi ican impac on p ope y selling p ice. Du ing model es ing and alida ion, he consequences o including o excluding ce ain ea u es we e e alua ed. A ibu es ha signi ican ly imp o ed p edic i e pe o mance o he models we e inco po a ed in o he inal inpu . This delibe a e selec ion ensu es ha he o ecas s a e op imized, as i ocuses on he ea u es ha exe he mos signi ican impac on he p edic ions, enhancing he o e all accu acy and eliabili y o he models. To de e mine he pe o mance me ics o he eg ession models, se e al me ics we e e alua ed. A e aining he model wi h he di e en o ecas models, add he p ice p edic ion o he da abase by c ea ing a new column "P edic ed Selling P ice". To op imize he pe o mance o ou machine lea ning models, an ex ensi e expe imen was conduc ed o e alua e a ious combina ions o hype pa ame e s. The objec i e was o iden i y he op imal se ings o each algo i hm, ensu ing ha he models we e well- uned and highly accu a e. Table 7 highligh s he speci ic hype pa ame e s used in he p edic ion model. Machine Lea ning Models Bes Hype pa ame e s Random Fo es Random S a e: 42. N es ima o s: 100. Min Samples Spli : 2. Min Samples Lea : 2. Max Fea u es: sq . C i e ion: MSE. Boo s ap: T ue Decision T ees Spli e : bes . Random S a e: 42. Min Samples Spli : 5. Min Samples Lea : 2. Max Fea u es: sq . C i e ion: MSE KNN Weigh s: uni o m. N neighbo s: 5. Me ic: minkowski. Lea size: 16. Algo i hm: kd_ ee Table 7 - Bes hype pa ame e s o he models 4.3. MODEL RESULTS P edic ed eal es a e p ices s a wi h all p ope ies in he da ase and use h ee di e en o ecas models: Random Fo es , Decision T ee and KNN. The esul s a e shown in Table 8. Random Fo es model achie ed he highes R² sco e, 82,34% which indica es ha app oxima ely 82% o housing p ices can be explained by he co ela ed a iables. By compa ing he p ice be ween “Obse ed Selling P ice” and he model p edic ed p ice, and e alua ing his p ice compa ison using he MAE me ic, i is ound ha he MAE be ween he es ima ed p ice and he p edic ed p ice is 21.969€. 38 Figu e 24 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices in No h using Random Fo es Figu e 25 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices in Cen e using Random Fo es 39 Figu e 26 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices in Alen ejo using Random Fo es Figu e 27 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices in Alga e using Random Fo es The sca e plo in Figu es 22 o 27 demons a es uni o mi y along he egions, exhibi ing simila pa e ns o each egion, wi h he Alga e egion displaying a highe dispe sion o poin s, pa icula ly hose de ia ing om he diagonal line. His og ams in Figu es 22 o 27, o di e en egions illus a e a ying dis ibu ions. The Alen ejo egion p esen s highe densi y wi h mul iple columns concen a ed nea ze o, whe eas he o he egions p edominan ly exhibi a p ima y column nea ze o, complemen ed by smalle ba s a ound his cen al poin . These obse a ions sugges ha he model po en ially showcases highe accu acy and consis ency in p edic ing p ope y p ices wi hin he Alen ejo egion compa ed o o he egions. 40 4.3.1.3. Model pe o mance o e iew in he p ope y ypes Figu e 28 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices in Lisbon Apa men s using Random Fo es Figu e 29 - Sca e plo and His og am o esiduals o p edic ing eal es a e p ices in Lisbon Houses using Random Fo es F om he sca e plo in Figu es 28 and 29 o apa men s and houses, i is appa en ha bo h exhibi simila cha ac e is ics wi h a concen a ion o poin s a ound ze o and an alignmen along he diagonal line. The his og am in Figu es 28 and 29 o apa men s e eals wo signi ican ly all columns concen a ed a ound ze o. On he o he hand, in he case o houses, a p ominen column cen e ed a ze o is ollowed by smalle columns in he icini y o ze o. This implies ha p edic ions o apa men s and houses a e mos ly close o he ac ual alues, showcasing highe accu acy in p edic ions o bo h p ope y ypes. The mo e p ominen columns a ound ze o signi y a highe equency o p edic ions close o he ac ual p ices, demons a ing mo e consis en pe o mance in p edic ing p ope y p ices, in bo h models, wi h a signi ican ly lowe e o . 41 This s udy shows ha among he h ee eal es a e p ope y p ice p edic ion models analyzed (Random Fo es , Decision T ee and KNN), he Random Fo es model becomes he i s choice o eal es a e p ice p edic ion. The esul s o he sca e plo and his og am analysis show ha he p edic ion pe o mance o he wo p ope y ypes, apa men s, and houses, is consis en , wi h de ia ions close o ze o. Alignmen along he diagonal shows ha he p edic ed and ac ual alues o he wo models a e in good ag eemen . These g aphical obse a ions a e consis en wi h he s a is ical esul s p esen ed in able 8, whe e he Random Fo es model has he lowes e o ma gin, ollowed by he Decision T ee model, while he KNN model has ela i ely high p edic ion e o s. Co ela ing hese g aphical obse a ions wi h he s a is ical me ics p esen ed ea lie , in able 8, i is clea ha Random Fo es models consis en ly ou pe o m Decision T ee and KNN models. The poin s a ound he ze o poin in he sca e plo and he highe columns in he his og am a e signi ican ly concen a ed, especially in he case o Random Fo es , con i ming he high p edic ion accu acy. This is consis en wi h he esul s o he pe o mance able and suppo s he conclusion ha he Random Fo es model has a lowe e o a e compa ed o o he models, making i he mos eliable model o p edic ing p ope y eal es a e p ices. 42 5. CONCLUSIONS AND FUTURE WORKS The pu pose o his s udy was o p edic eal es a e p ope y p ices and gain a deepe unde s anding o he Po uguese p ope y ma ke . To achie e his goal, a ho ough in es iga ion was conduc ed in o he mos app op ia e me hods o handling he da a a hand, conside ing he na u e and his o ical con ex o he da a. The li e a u e e iew plays a c ucial ole in selec ing he di e en me hods ha bes sui he esea ch objec i es. Da a p ep ocessing includes da a cleaning, explo a o y da a analysis, and examina ion o ends and co ela ions o e ime. This allowed us o calcula e p ope y p ices ac oss Po ugal and analyze di e ences be ween egions, highligh ing he impac o di e en a iables and geog aphical ea u es on p ice dispa i ies. The esul s ob ained om he p edic i e models demons a ed he e ec i eness o he chosen app oach. These models show ex emely high accu acy, wi h ew, ela i ely mino e o s, which may ha e limi ed impac wi hin he con ex o he eal es a e ma ke . This main ad an age o his s udy is he abili y o p edic u u e de elopmen s and p o ide cus ome s wi h aluable insigh s o make in o med decisions. This ou come is consis en wi h he main objec i es o he p ojec . Despi e i s impo an indings, his wo k has ce ain limi a ions ha mus be acknowledged. Some ha e o do wi h he da ase i sel . In pa icula , he lack o ce ain cha ac e is ics, such as he numbe o ba h ooms, he p esence o an ele a o o he loo s o he p ope y, c ea es challenges in de e mining he p ice o a p ope y. Due o he omission o hese a iables and he lack o clea co ela ions in he da a se , hese ea u es we e no added. Fu he mo e, he da ase con ains a la ge numbe o missing alues, making da a impu a ion a complex and less eliable p ocess. While po en ially aluable, excluding la i ude and longi ude da a can p o ide p ecise geog aphic coo dina es ha allow you o de e mine he exac loca ion o a p ope y. In many cases, his in o ma ion can be de i ed om pos al codes al eady included in he da a se . Howe e , i is impo an o no e ha pos al codes co e la ge a eas and di e en p ope ies wi hin he same pos al code may ha e di e en coo dina es. Fo example, wo houses wi h he same zip code bu loca ed on opposi e sides o a s ee o in di e en buildings will ha e di e en la i ude and longi ude coo dina es. The e o e, he accu acy o la i ude and longi ude in his da ase is inconsis en . Fu u e wo k should ocus on using coo dina es o imp o e accu acy. Economic, poli ical, and social ac o s also ha e a signi ican impac on he eal es a e ma ke o e ime. Models based on his o ical da a may no accu a ely p edic such changes. Fu he mo e, he skewed p ice dis ibu ion o he da ase a ec s o ecas accu acy, especially in ex eme cases. This s udy ma ks an impo an s ep in ully unde s anding he Po uguese dynamic eal es a e ma ke . By using he powe o p edic i e models and geospa ial da a, is possible o p o ide aluable insigh s o cus ome s and s akeholde s o shape a mo e well-known eal es a e ma ke . In iew o hese limi a ions, i is impo an o ealize ha his s udy ep esen s a snapsho o he dynamic eal es a e ma ke and p o ides he ounda ion o u u e wo k and imp o emen . 43 Realizing his wo k b ings i close o he ul ima e goal: o help indi iduals, companies and in es o s make da a-o ien ed decisions in dynamic and changing eal es a e landscape. I hope his esea ch can suppo and encou age u he esea ch in his ield. 44 BIBLIOGRAPHICAL REFERENCES Agnello, L., & Schuknech , L. (2011). Booms and bus s in housing ma ke s: De e minan s and implica ions. Ahmad, N., Menegaki, A. N., & Al-Muha ami, S. (2020). Sys ema ic Li e a u e Re iew o Tou ism G ow h Nexus: An O e iew o he Li e a u e and a Con en Analysis o 100 Mos In luen ial Pape s. Jou nal o Economic Su eys, 34(5), 1068–1110. h ps://doi.o g/10.1111/joes.12386 Ahn, J. J., Byun, H. W., Oh, K. J., & Kim, T. Y. (2012). Using idge eg ession wi h gene ic algo i hm o enhance eal es a e app aisal o ecas ing. 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