This refers to the efforts and procedures that survey researchers put in place to ensure the quality and accuracy of data being collected using the methodologies chosen for a particular study. Quality-control efforts vary from study to study and can be applied to questionnaires and the computerized programs that control them, sample management systems to ensure proper case processing, the monitoring of appropriate interviewer behavior, and other quality-control aspects of the survey process, all of which can affect the quality of data and thus the results. Proper training of interviewers is often seen as the heart of quality control, so is the team’s motivation. Our policy is that at least 10 percent of the interviews are conducted in the presence of the team leaders; and another 15 percent of all the questionnaires are back-checked on (either in person or by telephone).