Additional information on:
Van de Schoot, R., Yerkes, M.A., Mouw, J.M. & Sonneveld, H. (2013). What Took Them So Long? Explaining PhD Delays among Doctoral Candidates. PLoS One, 8(7): e68839. doi:10.1371/journal.pone.0068839
Link to article
In our paper we could have been more explicit about the differences between the total sample size as reported in the first sentence of the participant section of Study 1 and the actual sample size used in the analyses. There is data available on 565 PhD recipients, however we only used 331 cases in the analyses. The difference is caused by: two outliers (see also the participant section), 72 cases with missing data on all variables used in the analyses, 53 with no information about their gender, and 107 cases with missing information about the start and end date of their project time.