Drawing on classic and modern research from cognitive psychology, social psychology, and survey methodology, this book examines the psychological roots of survey data, how survey responses are formulated, and how seemingly unimportant features of the survey can affect the answers obtained. Topics include the comprehension of survey questions, the recall of relevant facts and beliefs, estimation and inferential processes people use to answer survey questions, the sources of the apparent instability of public opinion, the difficulties in getting responses into the required format, and distortions introduced into surveys by deliberate misreporting.