Inequality Over a Long Period

Chapter 6 explores the challenges involved in extending the time period of analysis to a longer number of years. In particular, data coverage and definitions used by statistical agencies change over time, so that comparable results are often difficult to obtain. As seen in Chapter 5, New Zealand income inequality increased during the late 1980s and early 1990s, but there has been limited change thereafter. Little is known about the levels and changes in inequality over prior decades. Such a long term analysis is restricted by the more limited data availability in earlier decades of the last century. Based on previously unexplored data from Statistics New Zealand Official Yearbooks, and Inland Revenue, this chapter reports estimates for the Gini index of income inequality for New Zealand from the mid-1930s to the present. Comparisons with estimates for Australia for 1942-2001 reveal some remarkable common features.