The potential for improving response rates by changing from one mode of data collection to another mode and the consequences for measurement and nonresponse errors are examined. Data collection from 8999 households was done in two phases. Phase 1 data collection was conducted by telephone interview, mail, interactive voice response, or the Internet, while Phase 2 focused on nonrespondents to Phase 1, and was conducted by a different mode, either telephone or mail. Results from our study suggest that switching to a second mode is an effective means of improving response. We also find that for the satisfaction–dissatisfaction questions asked in this survey, respondents to the aural modes (telephone and IVR) are significantly more likely than are respondents to the visual modes (mail and web) to give extreme positive responses, a difference that cannot be accounted for by a tendency towards recency effects with telephone. In general, switching to a second mode of data collection was not an effective means of reducing nonresponse error based on demographics.