Take this claim apart

A single claim you need to know whether to trust.

Take the claim below apart. Give me the evidence that supports it, the evidence against it, and the parts that are simply asserted with nothing behind them. Then a one-line verdict: well supported, contested, or thin. No hedging in the verdict, and no invented studies to fill the gaps.

Claim:

Testing a claim. Statistics, causal stories, methodology, and tracing a repeated claim back to where it started.