9/21/2017 When answers are estimated by rule of thumb: The analysis of estimated values in surveys In the 2009/2010 survey waves of the National Educational Panel Study (NEPS), roughly 70% of adult respondents replied to the question about their income with an approximate value—a common phenomenon also in other surveys. This distortion of the actual income distribution has a negative influence on the accuracy of the statistical analysis and relating conclusions. Dr. Sabine Zinn and Dr. Ariane Würbach of the Leibniz Institute for Educational Trajectories have developed a statistical model that allows researchers to make reliable statements about the actual income distribution even in the case of values rounded not at random. Read more about this in the series NEPS results compact.