Income distribution in Thailand is scale-invariant

This study examines whether income distribution in Thailand has a property of scale invariance or self-similarity across years. By using the data on income shares by quintile and by decile of Thailand from 1988 to 2021, the results from 306-pairwise Kolmogorov-Smirnov tests indicate that income distribution in Thailand is statistically scale-invariant or self-similar across years with p-values ranging between 0.988 and 1.000. Based on these empirical findings, this study would like to propose that, in order to change income distribution in Thailand whose pattern had been persisted for over three decades, the change itself cannot be gradual but has to be like a phase transition of substance in physics.

Automated summary

This study examines whether income distribution in Thailand exhibits scale invariance or self-similarity across years. Using data on income shares by quintile and decile from 1988 to 2021, the results of 306 pairwise Kolmogorov-Smirnov tests indicate that income distribution in Thailand is statistically scale-invariant or self-similar across years, with p-values ranging from 0.988 to 1.000. Based on these empirical findings, the study suggests that in order to change the persistent pattern of income distribution in Thailand over three decades, the change itself needs to be a phase transition similar to that in physics.