Taxes, Risk-Aversion, and the Size of the Underground Economy: A Nonparametric Analysis With New Zealand Data

We use nonparametric regression analysis to investigate the relationship between the effective tax rate and the relative size of the underground economy, using New Zealand data. The theoretical underpinnings of such a relationship are established by extending some of the predictions of the recent model of Trandel and Snow (1999) to allow for the form of the available aggregate data. Time-series evidence indicates that these data are non-stationary and cointegrated, and this is taken into account in our estimation. The theoretical framework produces an ambiguous prediction regarding the sign of the relationship we are studying. However, our nonparametric empirical analysis produces a positive and "S-shaped" relationship, and this supports earlier empirical studies that imposed such functional forms. The estimated model is used to simulate the effects of hypothetical tax changes on the size of the New Zealand underground economy, and to draw policy conclusions.