Traditional quality measures of survey instruments include item nonresponse and survey completion time. In interviewer-administered modes, quality measures sometimes include interviewer observations of respondent utterances or facial expressions. These results are often subjective and cannot describe the reasons behind respondents answer choices or their experiences with the survey. Use of paradata from Internet instruments allows us to get an objective view of the entire survey experience from initial login to final submission. As part of the 2012 National Census Test, the Census Bureau captured paradata from every pae of the online instrument, along with respondent answers. These paradata provide rich data related to respondent interaction with the census Internet questionnaire such as break-off rates, help link access, answer changes, and completion times. These data help researchers key in on items that are problematic from a user perspective in a way that is not possible with traditional data analyses, such as response rates. Paradata results allow researchers to focus instrument improvement efforts on items that are known to be problematic for a respondent in a very specific way. This paper will use paradata results from the 2012 National Census Test to identify potential issues that can be resolved for future online instruments and to highlight design features that worked well.