Measuring Inequality: Analysis of Wage Differentiation Data in Soviet Industry during the First Five-Year Plans

The article is devoted to studying the dynamics of wage differentiation among industrial workers in the USSR during the first two five-year plans. The primary focus is on analyzing to what extent the policy of combating "wage leveling" (уравниловка), proclaimed in 1931, led to a real increase in pay inequality. The source base consists of archival documents and statistical publications from the 1920s–1930s. The novelty of the work lies in the comprehensive use of quantitative methods to analyze wage policy at the intersection of two eras – the end of the NEP and forced industrialization – as well as in verifying the thesis of the "struggle against wage leveling" using specific statistical data on industries and regions. The study analyzes wage differentiation indicators in Soviet industry as a whole, in key industries (coal mining, metallurgy), and at the regional level. Statistical tools for measuring inequality are applied: the Gini index and the decile coefficient; Lorenz curves are constructed for visualization. The Appendix to the article describes the methodological problems of working with interval statistical data and proposes an algorithm, developed by the authors in Python, for calculating inequality indicators with varying structures of initial interval data on the distribution of workers by wage level. The results of the analysis lead to the following conclusions: in the late 1920s and early 1930s, the leveling tendency that began during the NEP years generally persisted; at the industry level, a turning point emerged in the early 1930s – wages in priority heavy industry sectors began to grow at an accelerated pace. From a regional perspective, data analysis for the Kuzbass coal industry in 1935 showed a higher level of differentiation compared to the late 1920s, indicating the implementation of a policy related to increasing the role of material incentives for labor. This is also evidenced, in particular, by the dynamics of the wage ratio between highly-skilled and low-skilled workers.