I recently took a class that focused mostly on linear regression, and it seems like regressions are very, very easy to manipulate, even unintentionally. Just by choosing different combinations of variables, or omitting vs. including some variables, I can dramatically affect regression results. Even further, this article on FiveThirtyEight describes "p-hacking" and shows how scientists can (often unintentionally) bias their regression results toward results that confirm their biases.
As an example, the article describes a study where several different research groups studied the relationship between race and red cards in football games, and says that because almost every group found significant results in the same direction, that's likely the truth. But isn't it possible that, even though the result makes sense, each of the scientists is just independently confirming their own bias and arriving at the same conclusion?
Can regression results ever be trusted?
(Note: this question was originally asked on Academia StackExchange, which is the wrong place.)