The high rate of failure to replicate is not, in and of itself, evidence of fraud. It’s primarily a problem with low power to detect plausible effects (ie small sample sizes). That’s not to say there isn’t much deliberate fraud or p-hacking going on, there’s far too much. But the so-called replication crisis was entirely predictable without needing to assume any wrongdoing. It happened primarily because most researchers don’t fully understand the statistics they are using.
The high rate of failure to replicate is not, in and of itself, evidence of fraud. It’s primarily a problem with low power to detect plausible effects (ie small sample sizes). That’s not to say there isn’t much deliberate fraud or p-hacking going on, there’s far too much. But the so-called replication crisis was entirely predictable without needing to assume any wrongdoing. It happened primarily because most researchers don’t fully understand the statistics they are using.
There was a good paper published on this recently: Understanding the Replication Crisis as a Base Rate Fallacy
And this is a nice simple explanation of the base rate fallacy for anyone who can’t access the paper: The p value and the base rate fallacy
tl;dr p<0.05 does not mean what most researchers think it means