  Selection into samples undermines efforts to describe populations and to
estimate relationships between variables. We develop a simple method for
correcting for sample selection that explains differences in survey responses
between early and late respondents with correlation between potential responses
and preference for survey response. Our method relies on researchers observing
the number of data collection attempts prior to each individual's survey
response rather than covariates that affect response rates without affecting
potential responses. Applying our method to a survey of entrepreneurial
aspirations among undergraduates at University of Wisconsin-Madison, we find
suggestive evidence that the entrepreneurial aspiration rate is larger among
survey respondents than the population, as well as the male-female gender gap
in the entrepreneurial aspiration rate, which we estimate as 21 percentage
points in the sample and 19 percentage points in the population. Our results
suggest that the male-female gap in entrepreneurial aspirations arises prior to
direct exposure to the labor market.
