Conversion of non-respondents in an ongoing panel survey: The case of the German Socio-Economic Panel (SOEP)

The results of a resurvey of non-respondents to the SOEP study carried out in 2006 show that this special effort of reinterviewing was relatively ineffective in two respects. First, the rate of successful conversions of passive to active respondents was low (less than 20 percent). Second, the composition of the longitudinal file did not improve. The same groups that showed high dropout rates in the SOEP (particularly low-income respondents and respondents in major cities) showed lower conversion rates in the resurvey. The resulting file of active respondents after the resurvey is therefore even more selective than the original file with regard to population means. Furthermore, due to the low rate of resurveying, the resurvey did not significantly improve the overall statistical power of the SOEP sample. In sum, the resurvey was an interesting experiment, but it shows little potential as a means for improving the standard fieldwork of SOEP.