solution
Custom cleaning
According to Johan Harristhal of Gfk Custom Research (www.gfk.com/gfkcr), completed questionnaires from the field often have many small errors because of the inconsistent quality of interviewing. For example, qualifying responses are not circled, or skip patterns are not followed accurately. These small errors can be costly. When responses from such questionnaires are put onto a computer, Custom Research runs a cleaning program that checks for completedness and logic. Discrepancies are identified on a computer printout, which is checked by the tabulation supervisors. Once the errors are identified, appropriate corrective action is taken before data analysis is carried out. Custom Research has found that this procedure substantially increases the quality of statistical results.