In research, it’s common to use self-report (having study participants report on their own characteristics, like weight). Self-report is definitely less expensive and more convenient than having researchers measure the characteristic in question. But is self-report accurate?
When it comes to weight, self-reported weight is generally highly correlated with researcher-measured weight. That said, there is some evidence that individuals at higher weights tend to under-report their weight (i.e., report a number that is lower than the one obtained when their weight is measured by a researcher). Conversely, individuals at lower weights, such as individuals with anorexia nervosa, may over-report their weight (i.e., report a number that is higher than the one obtained when their weight is measured by a researcher).
A recent study from the University of Alabama at Birmingham suggests that self-report of weight and height leads to incorrect conclusions about regional obesity rates. For example, for the South Atlantic region, a collection of states including North Carolina, obesity rates based on researcher-measured height and weight were over 5% higher than obesity rates based on self-reported height and weight.
Does this mean researchers should stop using self-report? In my experience, self-report is more problematic when you’re interested in using the characteristic in question (e.g., weight) to categorize participants into one group or another (e.g., not obese or obese). However, when you’re interested in relating that characteristic to something else (e.g., looking at how weight relates to being breast-fed as a child), the use of self-report can be less problematic.
It’s important that researchers relying on self-report make efforts to increase its accuracy. When doing so, researchers should consider two different sources of inaccuracy: misinformation (when participants don’t have accurate information) and misrepresentation (when participants intentionally report inaccurate information). Researchers can employ a variety of strategies to reduce both sources of inaccuracy, such as using rewards to incentivize accurate reports. Further, technology holds the potential to help researchers move away from reliance on self-report, as seen with wearable cameras that can be used to track diet, as well as other lifestyle factors.
By: Dr. Kristin Javaras
Le, A., Judd, S.E., Allison, D.B., Oza-Frank, R., Affuso, O., Safford, M. M., Howard, V. J., & Howard, G. (in press). The geographic distribution of obesity in the US and the potential regional differences in misreporting of obesity. Obesity. DOI: 10.1002/oby.20451
Stone, A. A., Bachrach, C. A., Jobe, J. B., Kurtzman, H. S., & Cain, V. S. (2000). The science of self-report: Implications for research and practice. Mahwah, NJ: Lawrence Erlbaum Associates.