Translation of "preliminary study" into German

In Ireland, the sample size tested was much smaller because it was only part on the preliminary study.

In Irland war die untersuchte Stichprobe erheblich kleiner, weil sie nur Teil der Vorstudie war.

However, several methodological problems were encountered and required extensive preliminary studies.

Dabei ergaben sich methodische Schwierigkeiten, die zahlreiche Voruntersuchungen notwendig machten.