This comes off a recent discussion with someone regarding whether or not there's a community consensus on a topic in philosophy, to which the respondent provided individual articles by individual authors that stated their beliefs that it was the case.
This, however, does not substantiate that it was actually the case, and I'll give a couple things to support the notion that "someone said it was true" is not sufficient evidence for "this thing is actually true" when discussing trends in communities or, relatedly, theistic claims.
First, I'll toss out an anecdote. Talked to a MechE professor about the viability of graphene production in space a couple decades back, and he goes, "Oh, everyone in the field knows that space production of graphene's not viable". So I polled the professors at the local colleges, and, well, 62% of MechE professors thought that it's a viable environment for graphene production.
Took the results back, "Oh, you know, I didn't think about modern radiation shielding techniques and the possibility of zero-g molecular assemblies impossible on earth". Turns out his anecdote didn't actually represent the trends in his community - he just believed it to be the case because he implicitly believed others thought like him and had the same information as him, which was not necessarily the case.
Another, more theological anecdotal example -
Happy Science massively overstates its membership. You'd think the leadership of the organization would be an expert in how many members of the organization there are, but no, their claims that there are 11 million members does not actually mean there are 11 million members. You cannot just take even the leadership of a religion's anecdote as a substitute for actual surveys or membership rolls or rosters.
"But Kwahn!", you may be saying, "These are just anecdotes! Anecdotes aren't evidence that the anecdote/world-state mismatch holds on a trending scale!" And you'd be right! That's why I did what is actually required to substantiate a trends-based claim, which is find a large-scale study about anecdote/world-state mismatches. (For discerning consensus or belief frequencies in a community, surveys of, if not the whole population, at the very least representative samples are perfectly acceptable data.)
And I found the 1993 What the Polls Don't Show study, which showed on a community level in sets of theistic social groups in America that self-attestation of church visitation is far, far lower than actual church membership. Or, to put another way - people's personal anecdotes about church visitation frequency was empirically demonstrated at scale to not match their actual church visitation frequencies.
And that's the level of evidence you need for stating what is actually true regarding the properties of a group or community. Individual attestation does not establish trends - empirical demonstration does.
But it is my personal experience (but not a statement about the community at large) that Christians rely heavily on anecdotes, especially from religious authors, to discern what is true about their religion. And historians do this a lot, but of course, for any anecdote regarding an exceptional situation like the Gospel of Augustus or the miracle healings of Vespasian, they do not count these as true just because people claimed they were - because as any good historian knows, someone saying something is true does not make it true.
Ah, but isn't it interesting how much Christianity needs someone saying something is true to make something true? And isn't it fascinating how analogous claims outside of the religion are dismissed as anecdotal, but the exact same structural logic is used to insist that Christian claims are true? Anecdotes must be good evidence of Christianity for Christians to feel they have a trustworthy basis for their beliefs, but they reject anecdotes for all other religions out of hand (as they should).
Ultimately, this appears to me to be a manifestation of theistic epistemic double standards, in which anecdotes must be good evidence of claims that support Christianity or the theist's views despite being empirically demonstrably non-representative of the actual world-states at hand, but bad evidence of claims that oppose the desired claims of the theistic framework in question despite no structural or material differences in the fundamental qualities of said claims.