The objective of the PDRC is to construct and collect a well-designed and large-scale panel data set and provide rigorous empirical studies based on these data sets. The data will enable us (i) to provide international comparisons and fact-findings on the household income changes, social mobility, changes in employment status and the investment activities; (ii) to verify the hypotheses related to the dynamics of economic behavior derived from economic theory; and (iii) to evaluate important policy changes in the tax system and social security program, which might have lagged effects.