We examine whether the magnitude of an anticipated income change affects consumption smoothing (the magnitude hypothesis). Although this hypothesis has been discussed for fifty years, we are one of the first to provide formal statistical evidence to support it. We consider the natural experiment of an individual's final mortgage payment, an anticipated income change, and examine how it affects credit card expenditure. We can identify causality because the dates of final mortgage payments across individuals are uncorrelated with unobserved determinants of consumption. Using an event study methodology, we provide evidence to support the magnitude hypothesis.

Recent research finds that poorer individuals make financial mistakes when the decisions are difficult and rare. We examine who makes financial mistakes involving decisions that are easier and more frequent – specifically, the inadvertent failure to pay monthly credit card balances when sufficient funds are available. On the one hand poorer individuals may make such mistakes because of lower levels of financial literacy. Alternatively, richer individuals may make such mistakes because of the relatively lower costs to them of such mistakes. We examine this question using confidential individual credit card statement data, with over a million data points. Our results show that poorer individuals are more likely to make these mistakes, even after controlling for education.