By Bryan Caplan
Two decades ago, economists started taking intelligence seriously. Now economists are starting to take conscientiousness seriously. Unfortunately, most existing data sets don’t contain personality tests. Even when they do, personality tests are only self-reports. Wouldn’t it be great if we could retrofit every existing data set with a behavioral measure of conscientiousness? Wouldn’t it be even better if we could do this for free?
If you asked me these questions a few months ago, I would have replied, “Alas, that’s impossible.” But GMU Ph.D. student David Hedengren has since changed my mind the old-fashioned way: By doing the supposedly “impossible.”
Hedengren’s* new working paper “The Dog that Didn’t Bark: What Item Non-Response Shows about Cognitive and Non-Cognitive Ability” hypothesizes that more conscientious people will try harder to completely answer surveys. As a result, the failure to answer survey questions tells us something about your character.
[S]urveys contain a valuable but neglected piece of data: what respondents do not say. Respondents skip, refuse to answer, or claim ignorance on at least a few questions in virtually all surveys. When a respondent forgets to fill in answers to some questions on the survey form, or refuses to provide an answer to the interviewer, we gain important information about respondents. For example information about how careful respondents are, how much they value privacy, and how open they are to sharing personal information with a stranger.
The beauty of this hypothesis is that you can test it with virtually any pre-existing data set – even data sets that don’t officially try to measure personality. Hedengren then applies his insight to two major surveys: the German Socio-Economic Panel (SOEP) and the Survey of Income and Program Participation (SIPP).
The SOEP already explicitly measures conscientiousness. Hedengren shows that his non-response measure alone is a better predictor of income than the SOEP’s self-reported conscientiousness:
We then test whether item response or conscientiousness and IQ, as measured in the SOEP, is a better predictor of economic outcomes. We find that item response is more strongly correlated with income than self-reported measures of conscientiousness. We also find that although item non-response is correlated with IQ it is not merely a proxy for IQ since it still is a significant predictor of earnings even after controlling for IQ.
The SIPP, in contrast, does not explicitly measure conscientiousness. But Hedengren’s measure is also a very good predictor of income in the SIPP as well as the SIPP Gold Standard (which uses administrative records instead of self-reports to measure income):
We demonstrate the potential usefulness of this metric by applying it to SIPP and the SIPP Gold Standard. In both self-reported personal income and annual earnings from administrative records, we show that item non-response is a consistent predictor of earnings with the same magnitude as graduating from high school relative to not graduating.
Predicting academic success is hard, but I’ve never been more confident that a GMU student’s working paper will end up in a top journal. Hedengren’s paper is a godsend for every empirical labor economist. They can immediately start using his novel metric, free of charge:
Our findings suggest that item-non response is a useful proxy for understanding human behavior. This proxy can be of great use to researchers since it already exists on every survey ever conducted without adding any additional respondent burden or data collection cost.
P.S. You should hire this man.
* “The Dog That Didn’t Bark” is co-authored with Thomas Stratmann, but Stratmann assures me that Hedengren originated the key idea and did the lion’s share of the work.