There are many stages in designing a survey and each influences survey quality. already gave an early warning of the complexity of the task facing the survey designer, when he listed no less than thirteen factors that affect the ultimate usefulness of a survey. Among those are the relatively well understood effects of sampling variability, but also more difficult to measure effects.
incorporates effects of the interviewer, method of data collection, nonresponse, questionnaire imperfections, processing errors and errors of interpretation.
basically classify threats to survey quality in two main categories, for instance
differentiating between errors of nonobservation and observation group errors in sampling error and nonsampling error.