Measurement and nonresponse error in panel surveys SIPP is considered by many to be a larger problem than in other types of survey data collection designs.  Responses in a single wave are subject to usual types of measurement error.  This “cross-section” measurement error is compounded by additional measurement problems that may arise when respondents are repeatedly interviewed.  It is suspected that as respondents are asked the same questions on successive waves, the way that they answer may change.  Respondents may become conditioned by the interviewing and change their behavior or responses.