The question of economic security for New Zealanders is not simply one of social assistance, but of whether the system overall results in buffers of a public and private nature that are adequate for the challenges of the current environment. This article examines this question through an analysis of the volatility of individual incomes in New Zealand. It begins by explaining the concept of income volatility and its importance as an indicator of economic security. The data, methodology and findings of this analysis will then be explained, followed by a consideration of the limitations of this approach in terms of both measurement and the conclusions that can be drawn. The discussion section will address how this analysis relates to existing work on income mobility, examine other evidence that might contextualise the findings and suggest areas for future research.