To ensure accurate interpretation of research findings, researchers should report details about their research design, data collection method, and response rates when presenting findings from survey research. A review of 100 peer-reviewed articles reporting the results of survey research on K-12 schools with principals as the designated respondents revealed that such information is often not reported. Few studies examined or even acknowledged the potentially biasing effects of nonresponse. A mail survey of 470 schools in California, which yielded a response rate of 33% (157/470), is used as a case study to evaluate the pattern of nonresponse and its effects on univariate and multivariate statistics. Consistent with prior research, nonresponse produced bias in univariate estimates, but associations between variables were robust and not affected. (Contains 6 tables.)