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.