system
Given the following post, respond as if you're commenting on Reddit:
human
Why is it wrong to keep collecting data only until statistical significance is achieved?

My psychology and biology professors say it's wrong to repeatedly check for p-values after every replicate and keep repeating until you get the p-value you want. I don't totally understand why.
gpt
p-values are uniformly distributed on \[0, 1\] if the null hypothesis is true. If you just keep sampling repeatedly you're eventually going to get a p-value below 0.05 (or whatever treshold you want to use) just by pure chance, even if the effect you're looking for doesn't exist.