RT Journal Article SR Electronic T1 A Model for Diagnosing and Reducing Non-response Bias JF Journal of Advertising Research JO J Advert Res FD WARC SP 85 OP 93 DO 10.2501/JAR-40-1-2-85-93 VO 40 IS 1-2 A1 Richard Colombo YR 2000 UL http://www.journalofadvertisingresearch.com/content/40/1-2/85.abstract AB Perhaps the first question people ask when judging the quality of a sample survey is, ‘What is the sample size?’ Just as important, but one less often asked, is the question ‘What is the response rate?’. Response rate is important in assessing the non-response bias, which is independent of sample size and usually far exceeds sampling error as a source of uncertainty. This discussion paper looks at current ‘callback’ and weighting methods, and proposes a model to reduce response rate error.