Data quality is an assessment of data's fitness to serve its purpose. You can enable Duplicate IP Across Responses module to perform the quality check for all questions against the responses given from same IP address. This will help to identify the authenticity of the survey responses.
If you think the response should not have been flagged, you can unflag the response by clicking on the Response ID. Navigate to the data quality tab. This view will have the question, answer and the reason for flagging the response. Click on the Unflag Response button. Once the unflagging is done the flag icon will disappear in the response viewer.
To flag the response, click on Response ID. Navigate to data quality tab. Click on Flag Response button. Once the response is flagged, flag icon will appear with Response ID which has been flagged.
This feature is available with the following license :