This article compares the growth rates of Web of Science indexed research publications in 11 European countries from 2000 to 2015. The growth of publication output in the Czech Republic was very fast: the annual production increased more than threefold. However, the number of articles increased only 2.6-fold, whereas the number of proceedings papers increased eightfold. During 2013-15 almost one-third of the papers published by researchers based in the Czech Republic were proceedings papers, a much higher share than in any other benchmark country. Such a high share is undesirable, because proceedings papers are generally much less often cited than journal articles. The growth of the number of proceedings papers is fastest in 17 fields belonging to the social sciences which usually do not hold proceedings papers in high regard. Our analysis shows that this undesirable development started after the introduction of national performance-based research funding system (PRFS) in the Czech Republic. Hence, the effort made to publish proceedings papers seems to reflect an optimization strategy in the light of the PRFS. In the Czech PRFS, proceedings papers have been rewarded point values similar to articles in refereed journals and a large portion of the institutional funding is allocated according to the evaluation results. As a consequence of very fast growth of proceedings papers in the social sciences, the university institutional funding in these fields has grown faster than in other fields. In conclusion, the fast growth of proceedings papers represents an adaptive behavior to the context of the PRFS.