The Dog that Didn't Bark: What Item Nonresponse Shows about Cognitive and Non-Cognitive Ability

What survey respondents choose not to answer (item nonresponse) provides a useful task based measure of cognitive ability (e.g., IQ) and non-cognitive ability (e.g., Conscientiousness). Using the German Socio-Economic Panel (SOEP) and the National Longitudinal Survey of Youth 1997 (NLSY97), we find consistent correlation between item nonresponse and traditional measures of IQ and Conscientiousness. We also find that item nonresponse is more strongly correlated with earnings in the SOEP than traditional measures of either IQ or Conscientiousness. We also use the Survey of Income and Program Participation (SIPP) Gold Standard, which has no explicit measure of either cognitive or non-cognitive ability, to show that item nonresponse predicts earnings from self-reported and administrative sources. Consistent with previous work showing that Conscientiousness and IQ are positively associated with longevity, we document that item nonresponse is associated with decreased mortality risk. Our findings suggest that item nonresponse provides an important measure of cognitive and non-cognitive ability that is contained on every survey.