Which of those two sentences is correct?
- People were led into thinking that method X was beneficial for Y.
- People were led to think that method X was beneficial for Y.
Perhaps you also have an explanation why one or the other is correct?
It is safe to assume that all words unrelated to the question (words that are neither the preposition after "led" nor a form of the verb "think") are correct and there is no need to point out that those could be incorrect, depending on the context of use.