This paper examines the measurement of extreme poverty in Poland, focusing on the role of equivalence scales. The key research question is whether the original OECD equivalence scale, currently used by Statistics Poland, is consistent with the scale effects implied by the construction of the subsistence minimum across different household types. Using a oneparameter power equivalence scale, extreme poverty rates are recalculated under alternative assumptions based on anonymized microdata from the 2023 Household Budget Survey. The results indicate that the original OECD scale shows stronger economies than the one embedded in the subsistence minimum values, leading to substantial differences in the estimated extreme poverty rate. These findings underline the importance of a careful selection of equivalence scales in official poverty statistics, as methodological choices directly influence poverty assessment and the targeting of social policy.
equivalence scale, extreme poverty, subsistence minimum, household composition, poverty measurement
Ayala, L., Jurado, A., (2011). Pro-poor economic growth, inequality and fiscal policy: The case of Spanish regions. Regional Studies, 45(1), pp. 103–121. https://doi.org/10.1080/00343400903173209.
Biewen, M., Juhasz, A., (2017). Direct estimation of equivalence scales and more evidence on independence of base. Oxford Bulletin of Economics and Statistics, 79, pp. 875–905. https://doi.org/10.1111/obes.12166.
Bishop, J. A., Grodner, A., Liu, H. and Ahamdanech-Zarco, I., (2014). Subjective poverty equivalence scales for Euro Zone countries. Journal of Economic Inequality, 12(2), pp. 265–278. https://doi.org/10.1007/s10888-013-9254-7.
Buhmann, B., Rainwater, L., Schmaus, G., and Smeeding, T. M., (1988). Equivalence scales, well-being, inequality, and poverty: Sensitivity estimates across ten countries using the Luxembourg Income Study (LIS) database. Review of Income and Wealth, 34(2), pp. 115–142.
Calvi, R., Penglase, J., Tommasi, D. and Wolf, A., (2023). The more the poorer? Resource sharing and scale economies in large families. Journal of Development Economics, 160, 102986. https://doi.org/10.1016/j.jdeveco.2022.102986.
Coulter, F. A. E., Cowell, F. A. and Jenkins, S. P., (1992a). Differences in needs and assessment of income distribution. Bulletin of Economic Research, vol. 44(2), pp. 77–124. https://doi.org/10.1111/j.1467-8586.1992.tb00538.x.
Coulter F. A. E., Cowell F. A. and Jenkins S. P., (1992b). Equivalence scale relativities and the measurement of inequality and poverty. Economic Journal, (414), pp. 1067– 1082. https://doi.org/10.2307/2234376.
Deniszczuk, L., Sajkiewicz, B., (1997). The category of minimum subsistence. In: S. Golinowska (ed.), Poverty in Poland. Research findings. Institute of Labor and Social Affairs (in Polish).
de Vos, K., Zaidi, M. A., (1997). Equivalence scale sensitivity of poverty statistics for the member states of the European Community. Review of Income and Wealth, 43(3), pp. 319–333. https://doi.org/10.1111/j.1475-4991.1997.tb00222.x.
Deaton, A., Paxson, C., (1998). Economies of scale, household size, and the demand for food. Journal of Political Economy, 106(5), pp. 897–930. https://doi.org/10.1086/250035.
Donaldson, D., Pendakur, K., (2004). Equivalent-expenditure functions and expenditure- dependent equivalence scales. Journal of Public Economics, 88(1-2), pp. 175– 208. https://doi.org/10.1016/S0047-2727(02)00134-2.
Dudel, C., Garbuszus, J., Ott, N. and Werding, M., (2021). Income- (in)dependent equivalence scales and inequality measurement. German Economic Review, 22(2), pp. 235–255. https://doi.org/10.1515/ger-2020-0008.
Éltető, Ö., Havasi, É., (2002). Impact of choice of equivalence scale on income inequality and on poverty measures. Review of Sociology, 8(2), pp. 137–148. https://doi.org/10.1556/revsoc.8.2002.2.7.
Garbuszus, J. M., Ott, N., Pehle, S. and Werding, M., (2021). Income-dependent equivalence scales: A fresh look at German micro-data. Journal of Economic Inequality, 19, pp. 855–873. https://doi.org/10.1007/s10888-021-09494-7.
Hunter, B. H., Kennedy, S. and Smith, D., (2003). Household composition, equivalence scales and the reliability of income distributions: Some evidence for Indigenous and other Australians. Economic Record, 79(244), pp. 70–83. https://doi.org/10.1111/1475-4932.00079.
IPiSS, (2024). Information on the level and structure of the minimum subsistence level in 2023. Retrieved from: https://www.ipiss.com.pl/wp-content/uploads/2024/04/MEsrednioroczne-2023.pdf.
Kalbarczyk-Stęclik, M., Miśta, R. and Morawski, L., (2017). Subjective equivalence scale – cross-country and time differences. International Journal of Social Economics, 44(8), pp. 1092–1105. https://doi.org/10.1108/IJSE-09-2015-0251.
Koulovatianos, C., Schröder, C. and Schmidt, U., (2005). Properties of equivalence scales in different countries. Journal of Economics, 86(1), pp. 19–27. https://doi.org/10.1007/s00712-005-0141-y.
Kot, S. M., (2015). Equivalence scales based on stochastic indifference criterion: The case of Poland. Statistical Review, 62, pp. 263–280. https://doi.org/10.5604/01.3001.0014.1753.
Kot, S. M., (2023). Nonstandard Equivalence Scales and their Applications for European Union Countries, Gdańsk: Politechnika Gdańska.
Kurowski, P., (2022). The role of the social minimum and subsistence minimum in Poland in a historical perspective. Social Policy, XLIX(1), pp. 1–15. (in Polish) https://doi.org/10.5604/01.3001.0016.0915.
Lewbel, A., Pendakur, K., (2008). Equivalence scales. In S. N. Durlauf & L. E. Blume (Eds.), The New Palgrave Dictionary of Economics (2nd ed.). Palgrave Macmillan. https://doi.org/10.1057/978-1-349-95121-5_2056-1.
Morawski, L., (2018). Using subjective equivalence scales to analyze poverty in Poland. Argumenta Oeconomica, 41(2), pp. 139–160. https://doi.org/10.15611/aoe.2018.2.09.
Mysíková, M., Želinský, T., Garner, T. I. and Fialová, K., (2022). Subjective equivalence scales in Eastern versus Western European countries. Contemporary Economic Policy, 40(4), pp. 659–676. https://doi.org/10.1111/coep.12579.
Pendakur, K., (1999). Semiparametric estimates and tests of base-independent equivalence scales. Journal of Econometrics, 88(1), pp. 1–40. https://doi.org/10.1016/s0304-4076(98)00020-7.
Schröder, C., (2004). Variable Income Equivalence Scales. An Empirical Approach. Physica-Verlag, Heidelberg.
Statistics Poland, (2025) Concepts Used in Official Statistics: Equivalence Scales. Retrieved from: https://stat.gov.pl/metainformacje/slownik-pojec/pojecia-stosowanew-statystyce-publicznej/3204,pojecie.html.
Statistics Poland, (2024a). Methodological report. Household Budget Survey. Warsaw.
Statistics Poland, (2024b). The extent of economic poverty in Poland in 2023. Retrieved from: https://stat.gov.pl/obszary-tematyczne/warunki-zycia/ubostwo-pomoc-spoleczna/zasieg-ubostwa-ekonomicznego-w-polsce-w-2023-roku,14,11.html.
Szulc, A., (2006). Poverty in Poland during the 1990s: Are the results robust? Review of Income and Wealth, 52(3), pp. 423–448. https://doi.org/10.1111/j.1475-4991.2006.00197.x.
Szulc, A., (2009). A matching estimator of household equivalence scales, Economics Letters, 103, pp. 81-83. https://doi.org/10.1016/j.econlet.2009.01.027.
Szulc, A., (2014). Empirical versus policy equivalence scales: matching estimation. Bank i Kredyt, 1, pp. 37–52.
Ulman, P., (2012). Equivalence scale in terms of Polish households’ source of income. Folia Oeconomica Stetinensia, 10(2), pp. 114–127. https://doi.org/10.2478/v10031-011-0044-8.