The purpose of this project was to provide scientifically robust and practical information on the variability of the endpoints assessed in earthworm field studies, the statistical significance of the results and the level of the statistically detectable effects of the chemicals tested - with the aim of developing suggestions for improving the test design. Based on the results of the evaluation of existing data, a pilot field study was performed according to a newly developed combined NOEC- and ECx-test design with the test chemical carbendazim. According to the experiences made during the performance of the pilot study and the results of the statistical analyses, a draft OECD test.