I'm collaborating with a research management company to collect data using an online study. I have two experiments registered online, and want to run 75 participants through each. I included a wrap-up link at the end of the online experiments that refers participants back to a webpage of the research management company so thy can check how many participants have finished the study.
The problem now is that their numbers and my numbers don't match. According to their data (which I can also download), 150 participants have already reached the wrap-up link. However, when I look at my datafiles, I only have datafiles for about 100 participants.
We tried to figure out what this discrepancy could be due to, but we have no idea. For existing half-way the experiment doesn't bring people to the wrap-up links. I made sure that in the last section of my experiment, participants have to click a button on the screen to continue, so even if they do not enter any other responses, this button click is recorded.
I was hoping you could offer some suggestions as to what might cause the discrepancy in numbers.