Millisecond Forums

Hi,I am using participant number to run two different versions of the experiment (using the group attribute). I want equal numbers of odd and even participant numbers in order to have equal numbers for the different versions. After running about 80 participants online I noticed two things that are problematic: 1. Numbers are not assigned sequentially, creating non-equal numbers of participants in different versions. 2. One number has been used for 9 different participants. How is this possible? They participated at different times and even on different days.