During 2008 the Wyoming Survey & Analysis Center (WYSAC) at the University of Wyoming directed a national survey by telephone, on the Internet, and by mail, with a total of more than 3300 respondents nation-wide. The goal of the study is to assist the U.S. Environmental Protection Agency (EPA) in comparing traditional modes of administering a questionnaire with new survey methods that use recruited panels of Internet respondents. Specifically, EPA wants to assess the relative merits of these different survey approaches for estimating the general public‟s willingness to pay for environmental quality. The present study uses phone and mail samples drawn by Random Digit Dialing (RDD) for comparison with a sample from an Internet panel recruited by RDD. Each sample was administered a questionnaire developed by WYSAC that focused on the public‟s valuation of improved air quality in national parks. By design, the questionnaire is nearly identical for all three modes, and also allows comparisons on some items with a separate nation-wide telephone survey of over 4000 respondents that WYSAC conducted for the National Park Service. Controlling, insofar as possible, for mode differences in the demographic characteristics of respondents, we performed statistical tests for mode effects in reported behaviors and attitudes. We used econometric modeling to examine mode differences in willingness to pay to reduce ozone pollution in the parks. This report summarizes some relevant prior research, our methodology, and the main findings of the study. Several appendices present the methods and results in further detail.