What is preventing someone from having 200 participants, but saying they only had 100 participants, and then only providing evidence for 100 participants?
The researchers will have to have gone through some kind of third party agency to get the partecipants. This agency should be queried to see the number they report
How does this agency determine who can meaningfully participate in the study? Are they going to have the expertise to make that determination for _every_ study that could possibly be conducted?
What is the difference (to a layperson) between cherry-picking participants and rejecting participants because they do not meet your study's criteria?
Who funds this agency?
Do the members of the reviewing agency have their own biases, and might those biases tarnish the reputation of a study that is actually well-conducted? (hint: this already happens in journals)
Pfizer had a trial with 21823 people in the Expirement group and 21823 people in the Placebo group. In the results they excluded data for 1790 from the Expirement group and 1585 Placebo group. However, _crucially_ Pfizer never claimed there were only 100 people in the study after starting with 200; you know pfizer excluded 3375 people because _Pfizer told you_.
Every clinical trial paper I've read has a discussion of inclusion and exclusion criteria. I think for the trial to be registered, it has to include this information.
"unrelated reasons" should not be an acceptable excuse though. either state the reason or it goes into the trash. and if they were private reasons you can still contact them to confirm they left on their own volition and/or they didn't finish the trial without getting into specifics.
you only need one lie to suspect the whole thing
for example, if you have 50 partecipants but only provide the multimedia evidence for 20 of them your study should be thrown out the window