Funding for this research was provided by:
Institute for Employment Research (the Research Institute of the Federal Employment Agency in Germany).
Text and Data Mining valid from 2018-06-18
First Online: 18 June 2018
Compliance with Ethical Standards
: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
: Informed consent was obtained from all individual participants included in the study.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.