In oducing Dung’s Tou ism Balance Index (TBI) and Inbound–Ou bound
Balance (IOB): A New F amewo k o Measu ing In e na ional Tou ism
Equilib ium – P ep in e sion
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Au ho : T ần Anh Dũng (Saigon Uni e si y, Vie nam)
P ep in / Zenodo Ve sion 1.0
License: CC-BY 4.0
Email: [email protected]. n
ORCID: h ps://o cid.o g/0009-0001-4560-2385
Abs ac
Despi e in e na ional ou ism exceeding US$1.5 illion in 2024, no simple, bounded, and
globally compa able indica o exis s o e eal whe he a coun y is a ne ea ne o ne spende
in ou ism ade. Exis ing global ou ism s a is ics—such as a i als, depa u es, eceip s, and
expendi u es—p o ide aluable desc ip i e insigh s bu ail o cap u e he s uc u al balance
be ween inbound and ou bound ou ism lows. This gap has limi ed he abili y o esea che s
and policymake s o assess sus ainabili y, o ecas demand, op imize ca ying capaci y, and
compa e coun ies on a no malized scale.
This p ep in in oduces wo new indices:
The Tou ism Balance Index (TBI) is p oposed as a s anda dized measu e o ou ism equilib ium,
o mula ed as:
(1) Dung’s Tou ism Balance Index (TBI) = (R_Inbound – R_ou bound) / (R_Inbound +
R_ou bound), anging symme ically om –1 o +1 , o
TBI=𝑅𝑖𝑛−𝑅𝑜𝑢𝑡
𝑅𝑖𝑛+𝑅𝑜𝑢𝑡
and In pa allel, he Inbound–Ou bound Balance (IOB) exp esses he s uc u al a io:
(2) IOB = Inbound / Ou bound, a a io-scale measu e o
IOB= 𝑅𝑖𝑛
𝑅𝑜𝑢𝑡.
Toge he , TBI and IOB o m a globally compa able analy ical sys em capable o suppo ing
sus ainable planning, economic assessmen , esilience modeling, and long- e m ou ism policy.
These indica o s ep esen an ini ial concep ual con ibu ion and a call o u he empi ical
alida ion wi hin he in e na ional ou ism esea ch communi y.
Keywo ds: Tou ism Balance Index; Inbound–Ou bound Balance; in e na ional ou ism
lows; sus ainabili y indica o s; equilib ium modelling; a el pa e ns; ou ism s a is ics;
1. In oduc ion
In e na ional ou ism plays an inc easingly signi ican ole in global de elopmen , economic
g ow h, cul u al exchange, and in e na ional coope a ion. Howe e , despi e he a ailabili y o
ex ensi e ou ism da a om he UNWTO and na ional s a is ical agencies, no s anda dized
indica o cu en ly exis s o measu e he balance be ween inbound and ou bound ou ism lows.
Mos coun ies ely on sepa a e s a is ics o a i als, depa u es, eceip s, expendi u es, and
isi o nigh s, bu hese me ics—al hough impo an — emain agmen ed and do no p o ide
a clea unde s anding o whe he a na ional ou ism sys em is balanced, dependen , o
s uc u ally dis o ed.
This absence o an equilib ium indica o has esul ed in h ee majo limi a ions:
①. Lack o compa a i e benchma king ac oss coun ies and o e ime.
②. Di icul y in aligning ou ism g ow h wi h sus ainabili y and ca ying-capaci y
p inciples.
③. Inabili y o e alua e ulne abili y o shocks, such as pandemics, geopoli ical con lic s,
o economic c ises.
To add ess his gap, his s udy p oposes wo new indica o s:
• Dung’s Tou ism Balance Index (TBI)
• Dung’s Inbound–Ou bound Balance (IOB)
Bo h de eloped by T an Anh Dung, hese indica o s in oduce a igo ous ye accessible
amewo k o e alua ing in e na ional ou ism equilib ium. The ounda ional o mula ion o
he Tou ism Balance Index (TBI) was i s p esen ed in he book Tổng quan du lịch quốc ế
(O e iew o In e na ional Tou ism) by T an Anh Dung (2025), which p o ided he ini ial
concep ual basis o he indica o s. Building on ha ounda ion, he p esen s udy u he
sys ema izes, o malizes, and in e na ionalizes he model. By in eg a ing no malized a ios and
equilib ium logic, TBI and IOB es ablish a uni ied analy ical app oach ha enhances c oss-
coun y compa abili y, suppo s sus ainable ou ism planning, and enables mo e consis en
benchma king wi hin global ou ism esea ch.
2. Concep ual Backg ound
2.1 Limi a ions o Exis ing Tou ism Me ics
Exis ing ou ism indica o s emain la gely ancho ed in absolu e measu emen s—such as o al
a i als, eceip s, o expendi u es—wi hou cap u ing he s uc u al ela ionship be ween
inbound and ou bound lows. This c ea es se e al analy ical blind spo s. Coun ies wi h apidly
expanding inbound ou ism may appea success ul on pape while simul aneously acing se e e
o e ou ism isks, in as uc u e s ess, and en i onmen al deg ada ion. In con as , coun ies
wi h la ge ou bound lows o en o e look subs an ial o eign-exchange leakage, which weakens
domes ic ou ism indus ies ye emains in isible in con en ional me ics. Middle-income
na ions, meanwhile, ind i di icul o compa e hemsel es wi h ad anced economies because
cu en indica o s ail o no malize o di e ences in economic scale, popula ion, o ou ism
ma u i y. These limi a ions e eal a pe sis en gap in ou ism science: he absence o a
no malized, ela ional, equilib ium-based indica o capable o compa ing s uc u al ou ism
posi ions ac oss na ions and o e ime. Thus, a no malized and ela ional indica o has been
missing om ou ism science.
2.2 Tou ism Equilib ium as a Policy Concep
A na ional ou ism sys em can be concep ualized as he dynamic in e ac ion o wo co e lows:
inbound ou ism (R_in), which gene a es e enue bu imposes p essu e on in as uc u e,
ecosys ems, and cul u al asse s; and ou bound ou ism (R_ou ), which e lec s ising li ing
s anda ds ye channels domes ic expendi u e ab oad while educing local conges ion. Tou ism
equilib ium eme ges when hese lows e ol e in a manne consis en wi h a coun y’s ca ying
capaci y, sus ainable de elopmen goals (SDGs), economic s uc u e, popula ion size,
in as uc u e capabili y, and long- e m na ional s a egy. This pe spec i e e ames ou ism no
as a unidi ec ional pu sui o g ow h bu as a balanced beha iou al–economic sys em ha mus
be e alua ed ela i e o in e nal cons ain s and ex e nal dependencies. Such a concep ual shi
p o ides he heo e ical ounda ion o he de elopmen o he Tou ism Balance Index (TBI)
and Inbound–Ou bound Balance (IOB)— wo indica o s speci ically designed o quan i y he
di ec ion, magni ude, and s uc u al cohe ence o na ional ou ism dynamics. This p o ides he
heo e ical ounda ion o TBI and IOB.
3. Me hodology: De ining TBI and IOB
3.1 Dung’s Tou ism Balance Index (TBI)
TBI=𝑅𝑖𝑛−𝑅𝑜𝑢𝑡
𝑅𝑖𝑛+𝑅𝑜𝑢𝑡
Meaning o Rin and Rou
• Rin (Inbound Re enue Equi alen )
Rin ep esen s he o al alue o inbound ou ism o a coun y.
I con e s he numbe o inbound ou is a i als in o a common mone a y uni (billions o
dolla s) using a s anda dized scaling ac o . Think o Rin as: “How much economic alue he
coun y ea ns om o eign isi o s.”
• Rou (Ou bound Expendi u e Equi alen )
Rou ep esen s he o al alue o ou bound ou ism o a coun y.
I con e s he numbe o ou bound ou is depa u es in o billions o dolla s using he same
scaling ule. Think o Rou as: “How much economic alue he coun y loses when i s esiden s
a el ab oad.”
P ope ies o TBI:
• Ranges om –1 o +1.
• TBI = 0 → pe ec equilib ium.
• TBI > 0 → inbound-dominan s uc u e.
• TBI < 0 → ou bound-dominan s uc u e.
Table 3.1: In e p e a ion F amewo k
TBI Range
In e p e a ion
Policy Implica ion
–0.33 o –1.00
Ou bound-dominan
imbalance
Reduce leakage, s imula e
inbound
–0.3 o –0.1
Mild ou bound excess
Imp o e a ac i eness
–0.1 o +0.1
Sus ainable equilib ium
zone
Main ain balance
+0.1 o +0.3
Mode a e inbound g ow h
Moni o en i onmen &
capaci y
+0.33 o +1.00
High inbound dependency
Risk o o e ou ism
This segmen a ion allows TBI o ope a e as a policy ool and a sus ainabili y index.
• Di ec ly in e p e able: TBI = +0.60 means a coun y ea ns 60 % mo e han i spends
ab oad.
3.2. Inbound–Ou bound Balance (IOB)
IOB= 𝑅𝑖𝑛
𝑅𝑜𝑢𝑡.
• IOB = 1 → balanced lows
• IOB > 1 → inbound > ou bound o ea ns mo e han i spends
• IOB < 1 → ou bound > inbound o spends mo e han i ea ns
IOB o e s in ui i e s uc u al in e p e a ion, complemen ing TBI. IOB = 4.0 means a coun y
ea ns ou imes wha i spends.
In sum, Rin and Rou o m he ounda ional mone a y equi alen s o ou ism lows, ansla ing
inbound and ou bound ips in o a s anda dized, compa able scale. TBI cap u es bo h he
di ec ion and he in ensi y o imbalance, showing whe he a coun y is a ne ou ism ea ne o
spende —and how a i is om equilib ium. IOB complemen s his by exp essing he balance
as a simple a io, indica ing how many inbound- alue uni s a coun y gains o e e y ou bound-
alue uni i loses. Toge he , hese indica o s o e a cohe en , in ui i e amewo k o
unde s anding ou ism pe o mance, compe i i eness, and s uc u al s abili y.
3.3. Da a and Empi ical Resul s (2025)
Using panel da a om he 50 la ges ou ism economies (accoun ing o 92–95 % o global
lows, 2000–2025; sou ces: IMF BPM6, UN Tou ism, WTTC – all open da a), he 2025 TBI
anking is led by Kenya (+0.810), Tü kiye (+0.804), G eece (+0.780), Po ugal (+0.775), Egyp
(+0.666), Spain (+0.581), Vie nam (+0.571), Mo occo (+0.571), Thailand (+0.566), and Sou h
A ica (+0.556). The la ges de ici s a e eco ded by he Uni ed Kingdom (–0.339), China (–
0.337), Ge many (–0.198), and he Uni ed S a es (–0.111).
4. Applica ions o TBI and IOB
4.1 Tou ism Policy and Na ional Planning
The Tou ism Balance Index (TBI) p o ides go e nmen s wi h a s a egic, sys em-le el
diagnos ic ins umen capable o e ealing long- e m s uc u al imbalances in in e na ional
ou ism lows. Ins ead o elying on agmen ed indica o s—a i als, depa u es, eceip s,
expendi u es—TBI condenses beha iou al dynamics in o a single equilib ium me ic ha
di ec ly in o ms na ional planning. A pe sis en ly high TBI (e.g., abo e 0.3) signals he
eme gence o o e ou ism p essu es, indica ing he need o a ge ed isi o - low managemen ,
e ised in as uc u e in es men plans, and adap i e caps on inbound g ow h. Con e sely,
coun ies main aining a nega i e TBI ace ou bound-dominan pa e ns ha may jus i y
selec i e ou bound axa ion, incen i e packages o inbound di e si ica ion, o es uc u ing o
na ional b anding s a egies.
Th ough his lens, TBI and IOB unc ion as an in ui i e mac o-dashboa d ha is a mo e
ac ionable han mul i- a iable compe i i eness amewo ks. Go e nmen s can se equilib ium
a ge zones, in eg a e ou ism beha iou in o long- e m socio-economic planning, and o ecas
in as uc u e demand wi h signi ican ly g ea e accu acy. Ul ima ely, hese indica o s suppo
e idence-based in e en ions designed o s abilise he ou ism sys em a he han me ely
expand i .
4.2. Sus ainable De elopmen and En i onmen al Managemen
F om a sus ainabili y pe spec i e, TBI ope a ionalises he ela ionship be ween ou ism
beha iou and en i onmen al ca ying capaci y. High inbound-weigh ed sys ems— e lec ed in
ele a ed TBI sco es— end o ampli y isks such as ecological deg ada ion, cul u al e osion,
p essu e on he i age si es, and declining u ban li eabili y. By quan i ying imbalance, TBI
becomes an ea ly-wa ning ins umen ha enables policymake s o align ou ism g ow h wi h
he p inciples o SDG 8 (decen wo k and inclusi e g ow h), SDG 12 ( esponsible consump ion
and p oduc ion), and SDG 14 (ma ine ecosys em p o ec ion).
Ra he han ea ing sus ainabili y as an abs ac aspi a ion, TBI links beha iou al pa e ns o
angible en i onmen al h esholds. Coun ies can use he indica o o calib a e conse a ion
budge s, guide spa ial zoning, design isi o -dis ibu ion policies, and implemen di e en ia ed
en i onmen al ees. In his sense, TBI e ames sus ainabili y om a mo al discou se in o a
measu able sys em-go e nance challenge.
4.3. Tou ism Shock and Resilience Modelling
Du ing sys emic dis up ions—pandemics, geopoli ical con lic s, economic ecessions—TBI
o e s a compac ye analy ically powe ul me ic o modelling ulne abili y, shock in ensi y,
and eco e y ajec o ies. A sudden collapse in inbound lows p oduces isible shi s in TBI,
enabling esea che s and go e nmen s o diagnose exposu e o ex e nal shocks and e alua e
esilience mechanisms. Because TBI cap u es beha iou al equilib ium, i se es simul aneously
as a s ess indica o and a eco e y p oxy, e lec ing how quickly a na ional ou ism sys em
egains s uc u al balance.
This makes TBI pa icula ly aluable o building esilience scena ios, o ecas ing pos -c isis
mobili y pa e ns, and assessing he s abili y o ou ism-dependen economies. In sho , TBI
ans o ms c isis analysis om eac i e na a i e in o measu able, compa a i e, and policy-
ele an modelling.
5. Conclusion
In conclusion, Dung’s Tou ism Balance Index (TBI) and Dung’s Inbound–Ou bound Balance
(IOB) ep esen he i s simple, bounded, and globally compa able measu es o ou ism
equilib ium. Filling a 50-yea me hodological gap, hey o e policymake s and esea che s an
ac ionable ool o sus ainabili y assessmen , c isis managemen , and balanced compe i i eness
benchma king. I widely adop ed, TBI and IOB could become he “HDI o global ou ism”: a
new common language o e idence-based go e nance in he 21s cen u y.
Re e ences
Coghlan, A. (2019). Sus ainable ou ism policy amewo ks. T ong An in oduc ion o
sus ainable ou ism. h ps://doi.o g/10.23912/9781911396734-4242
C ouch, G. I., & Ri chie, J. R. B. (1999). Tou ism, compe i i eness, and socie al p ospe i y.
Jou nal o Business Resea ch, 44(3), 137–152. h ps://doi.o g/10.1016/S0148-
2963(97)00196-3
Dwye , L., & Fo sy h, P. (2011). Me hods o es ima ing des ina ion p ice compe i i eness: A
case o ho ses o cou ses? Cu en Issues in Tou ism, 14(8), 751–777.
h ps://doi.o g/10.1080/13683500.2011.586680
Mazanec, J. A., Wöbe , K., & Zins, A. H. (2007). Tou ism des ina ion compe i i eness: F om
de ini ion o explana ion? Jou nal o T a el Resea ch, 46(1), 86–95.
h ps://doi.o g/10.1177/0047287507302389
Pulido-Fe nández, J. I., & Rod íguez-Díaz, B. (2016). Rein e p e ing he des ina ion
compe i i eness index: A new p oposal based on he ou ism balance o ade. Tou ism
Economics, 22(5), 1035–1055. h ps://doi.o g/10.5367/ e.2015.0478
T ần Anh Dũng. (2025). Tổng quan du lịch quốc ế. Nhà xuấ bản Thuận Hóa. ISBN: 978-604-
353-975-2 (T an, A. D. (2025). O e iew o in e na ional ou ism. Thuan Hoa Publishing
House. ISBN 978-604-353-975-2.)
Webs e , C., & I ano , S. (2014). T ans o ming compe i i eness in o economic bene i s: Does
ou ism s imula e economic g ow h in mo e compe i i e des ina ions? Tou ism
Managemen , 40, 137–140. h ps://doi.o g/10.1016/j. ou man.2013.06.003
Wo ld Economic Fo um. (2024). T a el & Tou ism De elopmen Index 2024. Wo ld Economic
Fo um. h ps://www.we o um.o g/publica ions/ a el- ou ism-de elopmen -index-
2024/
Wo ld Tou ism O ganiza ion (UNWTO). (2021). In e na ional ou ism highligh s, 2020 edi ion.
h ps://doi.o g/10.18111/9789284422456
