The German Federal Government examines whether it is possible to issue a regulation for reasons of common welfare. The regulation should permit telephone and electronic services as under the existing laws. Reason for issuing such a regulation can be a high number of expected job losses. However, call centres and their employees cannot be completely identified within existing datasets. Therefore, it is not possible to forecast potential job losses. Hence, it is necessary to conduct a survey on the establishment level. There are two alternatives to conduct such a survey: First, the IAB-Establishment Panel can be extended and, second, a new survey can be conducted. Based on the results of the survey, it should be possible to quantify workers and hours worked. Furthermore, the composition of the workforce within call centres will become transparent. To forecast possible job losses additional methods need to be applied. However, no method will yield unambiguous results on its own. Therefore, we propose to apply a mixture of methods that runs the risk of a wide range of results that probably does not allow to draw any conclusions.