Source ethics debate

Parallel case: A sports-drink company posts a blog saying its new electrolyte mix "boosts endurance by 30 percent," citing three athletes who felt stronger. An independent study of 250 athletes, funded by a university and published in a peer-reviewed journal, found no measurable difference between the mix and plain water. Which source should you trust when deciding whether the endurance claim is real?\n\nClaim: I trust the independent peer-reviewed study more than the company blog when judging whether the endurance claim is true.\n\nEvidence: The study tested 250 athletes and compared the mix against a control group drinking plain water, and it measured endurance the same way for every participant. It was reviewed by outside experts before publication and was funded by a university, not the company selling the product. The blog rests on three athletes chosen by the company, with no control group, no shared way of measuring endurance, and a clear financial reason to report a positive result.\n\nReasoning: A trustworthy claim has to be measurable, repeatable, and free of obvious bias. A control group and a single measurement method let the study separate the effect of the drink from wishful thinking, and peer review plus outside funding reduce the chance that the result was shaped to sell a product. The blog gives none of that, so its three stories cannot rule out coincidence or bias. When two sources disagree, I weigh the one whose method controls for bias and whose results can be checked, which is why the peer-reviewed study decides it for me.