The Lake Wobegon Effect in Student Self-Reported Data
H/T Geary Behavior Blog
In a more recent paper (Journal of Economic Education, 2010), Haley, Johnson and McGee examine whether using student-survey data in place of official records data meaningfully biases regression estimates. They motivate their contribution by noting a useful statistical feature of overreporting on bounded variables such as grade point average. “Specifically, the misreports will be negatively correlated with the true grade point average, yielding a form of nonclassical measurement error that actually counteracts the bias.” The authors connect this observation to reliability ratios used in labour economics. In two applications, they find that it is unnecessary to correct for the bias from the Lake Wobegon effect because it is so small.