Measuring horizontal inequity in healthcare utilisation: a review of methodological developments and debates

  • Mohammad Habibullah PulokEmail author
  • Kees van Gool
  • Mohammad Hajizadeh
  • Sara Allin
  • Jane Hall
Original Paper


Equity in healthcare is an overarching goal of many healthcare systems around the world. Empirical studies of equity in healthcare utilisation primarily rely on the horizontal inequity (HI) approach which measures unequal utilisation of healthcare services by socioeconomic status (SES) for equal medical need. The HI method examines, quantifies, and explains inequity which is based on regression analysis, the concentration index, and the decomposition technique. However, this method is not beyond limitations and criticisms, and it has been subject to several methodological challenges in the past decade. This review presents a summary of the recent developments and debates on various methodological issues and their implications on the assessment of HI in healthcare utilisation. We discuss the key disputes centred on measurement scale of healthcare variables as well as the evolution of the decomposition technique. We also highlight the issues about the choice of variables as the indicator of SES in measuring inequity. This follows a discussion on the application of the longitudinal method and use of administrative data to quantify inequity. Future research could exploit the potential for health administrative data linked to social data to generate more comprehensive estimates of inequity across the healthcare continuum. This review would be helpful to guide future applied research to examine inequity in healthcare utilisation.


Inequity Healthcare utilisation Review Concentration index Methods 

JEL Classification

I10 I14 I18 D63 



We thank two anonymous referees for their insightful comments and reviews which have helped improving the quality of the paper.


Mohammad Habibullah Pulok acknowledges to receive generous Ph.D. stipends and scholarships from the Capital Markets Cooperative Research Centre (CMCRC), Australia, University of Technology Sydney (UTS), Australia, and the Australian Institute of Health and Welfare (AIHW). However, views and opinions expressed in this article are solely of the authors and do not necessarily represent the official position or policies of the funding agencies.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


  1. 1.
    Mcloughlin, V., Leatherman, S., Fletcher, M., Owen, J.W.: Improving performance using indicators. Recent experiences in the United States, the United Kingdom, and Australia. Int. J. Qual. Health Care 13, 455–462 (2001). CrossRefGoogle Scholar
  2. 2.
    Arah, O.A., Klazinga, N.S., Delnoij, D.M., Asbroek, A.T., Custers, T.: Conceptual frameworks for health systems performance: a quest for effectiveness, quality, and improvement. Int. J. Qual. Health Care. 15, 377–398 (2003)CrossRefGoogle Scholar
  3. 3.
    Kruk, M.E., Freedman, L.P.: Assessing health system performance in developing countries: a review of the literature. Health Policy 85, 263–276 (2008). CrossRefGoogle Scholar
  4. 4.
    Baum, F.E., Bégin, M., Houweling, T.A.J., Taylor, S.: Changes not for the fainthearted: reorienting health care systems toward health equity through action on the social determinants of health. Am. J. Public Health 99, 1967–1974 (2009). CrossRefGoogle Scholar
  5. 5.
    van Doorslaer, E., van Ourti, T.: Measuring inequality and inequity in health and health care. In: Glied, S., Smith, P.C. (eds.) The Oxford Handbook of Health Economics, pp. 837–869. Oxford University Press, Oxford (2011)Google Scholar
  6. 6.
    O’Donnell, O., van Doorslaer, E., Wagstaff, A., Lindelow, M.: Analyzing Health Equity Using Household Survey Data: A Guide to Techniques and their Implementation. The World Bank, Washington, D.C. (2008)Google Scholar
  7. 7.
    Mooney, G.H.: Equity in health care: confronting the confusion. Eff. Health Care. 1, 179–185 (1983)Google Scholar
  8. 8.
    Sutton, M.: Vertical and horizontal aspects of socio-economic inequity in general practitioner contacts in Scotland. Health Econ. 11, 537–549 (2002). CrossRefGoogle Scholar
  9. 9.
    Culyer, A.J.: Need: the idea won’t do—but we still need it. Soc. Sci. Med. 40, 727–730 (1995). CrossRefGoogle Scholar
  10. 10.
    Devaux, M., de Looper, M.: Income-related inequalities in health service utilisation in 19 OECD countries, 2008–2009. OECD Publishing, Paris (2012)Google Scholar
  11. 11.
    van Doorslaer, E., Wagstaff, A., van der Burg, H., Christiansen, T., De Graeve, D., Duchesne, I., Gerdtham, U.-G., Gerfin, M., Geurts, J., Gross, L., Häkkinen, U., John, J., Klavus, J., Leu, R.E., Nolan, B., O’Donnell, O., Propper, C., Puffer, F., Schellhorn, M., Sundberg, G., Winkelhake, O.: Equity in the delivery of health care in Europe and the US. J. Health Econ. 19, 553–583 (2000). CrossRefGoogle Scholar
  12. 12.
    Wagstaff, A., van Doorslaer, E.: Measuring and testing for inequity in the delivery of health care. J. Hum. Resour. 35, 716–733 (2000). CrossRefGoogle Scholar
  13. 13.
    Wagstaff, A., van Doorslaer, E., Paci, P.: On the measurement of horizontal inequity in the delivery of health care. J. Health Econ. 10, 169–205 (1991). CrossRefGoogle Scholar
  14. 14.
    Fleurbaey, M., Schokkaert, E.: Unfair inequalities in health and health care. J. Health Econ. 28, 73–90 (2009). CrossRefGoogle Scholar
  15. 15.
    Wagstaff, A., van Doorslaer, E., Paci, P.: Equity in the finance and delivery of health care: some tentative cross-country comparison. Oxf. Rev. Econ. Policy. 5, 89–112 (1989). CrossRefGoogle Scholar
  16. 16.
    Kakwani, N., Wagstaff, A., van Doorslaer, E.: Socioeconomic inequalities in health: measurement, computation, and statistical inference. J. Econom. 77, 87–103 (1997). CrossRefGoogle Scholar
  17. 17.
    Wagstaff, A., Paci, P., van Doorslaer, E.: On the measurement of inequalities in health. Soc. Sci. Med. 33, 545–557 (1991). CrossRefGoogle Scholar
  18. 18.
    van Doorslaer, E., Koolman, X., Jones, A.M.: Explaining income-related inequalities in doctor utilisation in Europe. Health Econ. 13, 629–647 (2004). CrossRefGoogle Scholar
  19. 19.
    Fortin, N., Lemieux, T., Firpo, S.: Decomposition methods in economics. In: Ashenfelter, O., Card, D. (eds.) Handbook of Labor Economics, pp. 1–102. North Holland, Amsterdam (2011)Google Scholar
  20. 20.
    Wagstaff, A., van Doorslaer, E., Watanabe, N.: On decomposing the causes of health sector inequalities with an application to malnutrition inequalities in Vietnam. J. Econ. 112, 207–223 (2003). CrossRefGoogle Scholar
  21. 21.
    Fleurbaey, M., Schokkaert, E.: Equity in health and health care. In: Pauly, M.V., Mcguire, T.G., Barros, P.P. (eds.) Handbook of Health Economics, pp. 1003–1092. Elsevier (North-Holland), Amsterdam (2011)Google Scholar
  22. 22.
    Pulok, M.H., Sabah, M.N.-U., Uddin, J., Enemark, U.: Progress in the utilization of antenatal and delivery care services in Bangladesh: where does the equity gap lie? BMC Pregnancy Childbirth 16, 200 (2016). CrossRefGoogle Scholar
  23. 23.
    Wagstaff, A., van Doorslaer, E.: Equity in health care finance and delivery. In: Culyer, A.J., Newhouse, J.P. (eds.) Handbook of Health Economics, pp. 1803–1862. Elsevier (North-Holland), Amsterdam (2000)Google Scholar
  24. 24.
    O’Donnell, O., van Doorslaer, E., Wagstaff, A.: Decomposition of inequalities in health and health care. In: Jones, Andrew M. (ed.) The Elgar Companion to Health Economics, pp. 179–191. Edward Elgar Publishing, Cheltenham (2012)Google Scholar
  25. 25.
    Wagstaff, A.: The bounds of the concentration index when the variable of interest is binary, with an application to immunization inequality. Health Econ. 14, 429–432 (2005). CrossRefGoogle Scholar
  26. 26.
    Kjellsson, G., Gerdtham, U.-G.: On correcting the concentration index for binary variables. J. Health Econ. 32, 659–670 (2013). CrossRefGoogle Scholar
  27. 27.
    Erreygers, G.: Correcting the concentration index. J. Health Econ. 28, 504–515 (2009). CrossRefGoogle Scholar
  28. 28.
    Erreygers, G., Van Ourti, T.: Measuring socioeconomic inequality in health, health care and health financing by means of rank-dependent indices: a recipe for good practice. J. Health Econ. 30, 685–694 (2011). CrossRefGoogle Scholar
  29. 29.
    Wagstaff, A.: Correcting the concentration index: a comment. J. Health Econ. 28, 516–520 (2009). CrossRefGoogle Scholar
  30. 30.
    Wagstaff, A.: The concentration index of a binary outcome revisited. Health Econ. 20, 1155–1160 (2011). CrossRefGoogle Scholar
  31. 31.
    Wagstaff, A.: Reply to Guido Erreygers and Tom Van Ourti’s comment on “The concentration index of a binary outcome revisited”. Health Econ. 20, 1166–1168 (2011). CrossRefGoogle Scholar
  32. 32.
    Erreygers, G.: Correcting the concentration index: a reply to Wagstaff. J. Health Econ. 28, 521–524 (2009). CrossRefGoogle Scholar
  33. 33.
    Erreygers, G.: Can a single indicator measure both attainment and shortfall inequality? J. Health Econ. 28, 885–893 (2009). CrossRefGoogle Scholar
  34. 34.
    Gravelle, H.: Measuring income related inequality in health: standardisation and the partial concentration index. Health Econ. 12, 803–819 (2003). CrossRefGoogle Scholar
  35. 35.
    Huber, H.: Decomposing the causes of inequalities in health care use: a micro-simulations approach. J. Health Econ. 27, 1605–1613 (2008). CrossRefGoogle Scholar
  36. 36.
    Abu-Zaineh, M., Mataria, A., Moatti, J.-P., Ventelou, B.: Measuring and decomposing socioeconomic inequality in healthcare delivery: a microsimulation approach with application to the Palestinian conflict-affected fragile setting. Soc. Sci. Med. 72, 133–141 (2011). CrossRefGoogle Scholar
  37. 37.
    Erreygers, G., Kessels, R.: Regression-based decompositions of rank-dependent indicators of socioeconomic inequality of health. In: Dias, P.R., O’Donnell, O. (eds.) Health and Inequality (Research on Economic Inequality, Volume 21), pp. 227–259. Emerald Group Publishing Limited, Bingley (2013)Google Scholar
  38. 38.
    Heckley, G., Gerdtham, U.-G., Kjellsson, G.: A general method for decomposing the causes of socioeconomic inequality in health. J. Health Econ. 48, 89–106 (2016). CrossRefGoogle Scholar
  39. 39.
    Bago D’Uva, T., Lindeboom, M., O’Donnell, O., van Doorslaer, E.: Education-related inequity in healthcare with heterogeneous reporting of health. J. R. Stat. Soc. Ser. A. Stat. Soc. 174, 639–664 (2011). CrossRefGoogle Scholar
  40. 40.
    Lindelow, M.: Sometimes more equal than others: how health inequalities depend on the choice of welfare indicators. Health Econ. 15, 263–279 (2006). CrossRefGoogle Scholar
  41. 41.
    van Doorslaer, E., O’Donnell, O.: Measurement and explanation of inequality in health and health care in low-income settings. In: Health Inequality and Development. pp. 20–44. Palgrave Macmillan, London (2011)Google Scholar
  42. 42.
    Walsh, B., Silles, M., O’Neill, C.: The role of private medical insurance in socio-economic inequalities in cancer screening utilisation in Ireland. Health Econ. 21, 1250–1256 (2012). CrossRefGoogle Scholar
  43. 43.
    Rodrigues, R., Ilinca, S., Schmidt, A.E.: Income-rich and wealth-poor? The impact of measures of socio-economic status in the analysis of the distribution of long-term care use among older people. Health Econ. 27, 637–646 (2018). CrossRefGoogle Scholar
  44. 44.
    Wagstaff, A., Watanabe, N.: What difference does the choice of SES make in health inequality measurement? Health Econ. 12, 885–890 (2003). CrossRefGoogle Scholar
  45. 45.
    Siegel, M., Mielck, A., Maier, W.: Individual income, area deprivation, and health: do income-related health inequalities vary by small area deprivation? Health Econ. 24, 1523–1530 (2015). CrossRefGoogle Scholar
  46. 46.
    Meadows, G.N., Enticott, J.C., Inder, B., Russell, G.M., Gurr, R.: Better access to mental health care and the failure of the Medicare principle of universality. Med. J. Aust. 202, 190–195 (2015). CrossRefGoogle Scholar
  47. 47.
    Allin, S., Masseria, C., Mossialos, E.: Measuring socioeconomic differences in use of health care services by wealth versus by income. Am. J. Public Health 99, 1849–1855 (2009). CrossRefGoogle Scholar
  48. 48.
    Chen, Z., Roy, K.: Calculating concentration index with repetitive values of indicators of economic welfare. J. Health Econ. 28, 169–175 (2009). CrossRefGoogle Scholar
  49. 49.
    Clarke, P., Van Ourti, T.: Calculating the concentration index when income is grouped. J. Health Econ. 29, 151–157 (2010). CrossRefGoogle Scholar
  50. 50.
    Bago d’Uva, T., Jones, A.M., van Doorslaer, E.: Measurement of horizontal inequity in health care utilisation using European panel data. J. Health Econ. 28, 280–289 (2009). CrossRefGoogle Scholar
  51. 51.
    Cookson, R., Laudicella, M., Donni, P.L.: Measuring change in health care equity using small-area administrative data—evidence from the English NHS 2001–2008. Soc. Sci. Med. 75, 1514–1522 (2012). CrossRefGoogle Scholar
  52. 52.
    Boerma, J.T., Sommerfelt, A.E.: Demographic and health surveys (DHS): contributions and limitations. World Health Stat. Q. 46, 222–226 (1993)Google Scholar
  53. 53.
    Dalziel, K., Li, J., Scott, A., Clarke, P.: Accuracy of patient recall for self-reported doctor visits: is shorter recall better? Health Econ. 27, 1684–1698 (2018). CrossRefGoogle Scholar
  54. 54.
    McGrail, K.M.: Income-related inequities: cross-sectional analyses of the use of medicare services in British Columbia in 1992 and 2002. Open Med. 2, e91–e98 (2008)Google Scholar
  55. 55.
    Cookson, R., Gutacker, N., Garcia-Armesto, S., Angulo-Pueyo, E., Christiansen, T., Bloor, K., Bernal-Delgado, E.: Socioeconomic inequality in hip replacement in four European countries from 2002 to 2009–area-level analysis of hospital data. Eur. J. Public Health. 25, 21–27 (2015). CrossRefGoogle Scholar
  56. 56.
    Cookson, R., Asaria, M., Ali, S., Shaw, R., Doran, T., Goldblatt, P.: Health equity monitoring for healthcare quality assurance. Soc. Sci. Med. 198, 148–156 (2018). CrossRefGoogle Scholar
  57. 57.
    Lumme, S., Manderbacka, K., Keskimäki, I.: Trends of relative and absolute socioeconomic equity in access to coronary revascularisations in 1995–2010 in Finland: a register study. Int. J. Equity Health 16, 37 (2017). CrossRefGoogle Scholar
  58. 58.
    Manderbacka, K., Arffman, M., Keskimäki, I.: Has socioeconomic equity increased in somatic specialist care: a register-based cohort study from Finland in 1995–2010. BMC Health Serv. Res. 14, 430 (2014). CrossRefGoogle Scholar
  59. 59.
    Manderbacka, K., Arffman, M., Leyland, A., McCallum, A., Keskimäki, I.: Change and persistence in healthcare inequities: access to elective surgery in Finland in 1992–2003. Scand. J. Public Health 37, 131–138 (2009). CrossRefGoogle Scholar
  60. 60.
    Cunningham, C.M., Hanley, G.E., Morgan, S.G.: Income inequities in end-of-life health care spending in British Columbia, Canada: a cross-sectional analysis, 2004-2006. Int. J. Equity Health 10, 12 (2011). CrossRefGoogle Scholar
  61. 61.
    Orueta, J.F., García-Álvarez, A., Alonso-Morán, E., Vallejo-Torres, L., Nuño-Solinis, R.: Socioeconomic variation in the burden of chronic conditions and health care provision–analyzing administrative individual level data from the Basque Country, Spain. BMC Public Health. 13, 870 (2013). CrossRefGoogle Scholar
  62. 62.
    Lumme, S., Leyland, A.H., Keskimäki, I.: Multilevel modeling of regional variation in equity in health care. Med. Care 46, 976–983 (2008). CrossRefGoogle Scholar
  63. 63.
    Wagstaff, A., van Doorslaer, E.: Equity in the finance of health care: some international comparisons. J. Health Econ. 11, 361–387 (1992). CrossRefGoogle Scholar
  64. 64.
    Ataguba, J.E. Distributional impact of health care finance in South Africa. PhD diss., University of Cape Town, Cape Town (2012)Google Scholar
  65. 65.
    American Diabetes Association: 6. Glycemic targets: standards of medical care in diabetes-2019. Diabetes Care. 42, S61–S70 (2019).
  66. 66.
    Allin, S., Hernández-Quevedo, C., Masseria, C.: Measuring equity of access to health care. In: Smith, P.C., Mossialos, E., Papanicolas, I., Leatherman, S. (eds.) Performance Measurement for Health System Improvement: Experiences, Challenges and Prospects, pp. 187–221. Cambridge University Press, Cambridge (2009)Google Scholar
  67. 67.
    Hernández-Quevedo, C., Papanicolas, I.: Conceptualizing and comparing equity across nations. In: Papanicolas, I., Smith, P.C. (eds.) Health System Performance Comparison An Agenda for Policy, Information and Research, pp. 183–222. Open University Press, Berkshire (2013)Google Scholar
  68. 68.
    OECD. Divided We Stand—Why Inequality Keeps Rising. Paris (2011). / Accessed Sept 2019

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.School of Health AdministrationDalhousie UniversityHalifaxCanada
  2. 2.Geriatric Medicine ResearchNova Scotia Health AuthorityHalifaxCanada
  3. 3.Centre for Health Economics Research and Evaluation (CHERE)University of Technology Sydney (UTS)SydneyAustralia
  4. 4.Institute of Health Policy, Management and EvaluationThe University of TorontoTorontoCanada

Personalised recommendations