So from my other question, I was told that under certain circumstances, you could trust Wikipedia. But then after a couple of answers, I started wondering how to figure out which sites have valid information. For example, a site like the Canadian Encyclopedia, I've heard that the information there is all true, but how should one trust that? Is it because it's a published encyclopedia. It'd be great if I could have a specific explanation for how a site (like the Canadian Encyclopedia) is a site that you can trust to get true (by true I mean by information that is real. So like Donald Trump was born on June 14th) information from.
I think what you are asking is about research. The answer will depend on what exactly you are researching.
Peer reviewed published research is considered 'true.' So, if you search for your topic in Google Scholar there is a very good chance that anything you find is true. (unless it has been retracted, e.g. the vaccine fiasco).
Google Scholar is dense, and you won't find it user friendly. But for many topics from economics to astronomy to health care, it is sort of a gold standard for the latest understanding of 'what is true.'
You can visit a research forum - for example on Absolute Writers. Positing your question there may (or may not) generate feedback and you can ask for specifics about how the responder knows what they are saying.
In general terms Wikipedia backs up their statements with references. These are the things listed at the bottom of the page. Let's say Wikipedia says:
Donald Trump was born on June 14.
You could go to reference #1, and there might be a link to his birth certificate. That's your evidence that the statement is true.
In even broader terms, what you are talking about is the research that goes into writing to make a book as good as it can be and this is great and valuable in a book (in my opinion).
You are also touching on the idea of critical thinking, and this also is fantastic. I like your question, very much.
The answer by DPT is very good and I would accept it as it is.
I add a general rule: you can't know what is true or not unless you can cross-check your information with other information.
Good resources, such as academic, contain references to other works, which confirm or prove the given information. If you don't have references, you can widen your study by reading more stuff about the subject - for instance, don't rely on one newspaper, but read many of them, to see the differences in the telling of the same event. This will not give you the truth but will give you more elements to analyze.
To understand if a certain source of the website is reliable, it requires a certain experience, but an easy answer can come from the external elements of the website, such as:
- Who wrote the piece, or the other pages on the site? Is it a reliable author?
- Is the piece written in good and correct English (or any language), or does it contain misspellings and/or errors?
- what other articles are published on that site? Are they good or are they sketchy?
- are the tone and style exaggerated, or over-emphatic, or very broad and generic? Or is it measured and rationale?
These elements can give you a hint about the quality and reliability of the source. The IFLA (International Federation of Libraries Associations) produced a very nice poster on "how to spot fake news", which works also to address the quality of a source: https://www.ifla.org/publications/node/11174
It would be wonderful if there was a simple answer to this question. Unfortunately, there isn't.
Scientists and scholars put a lot of weight on the idea of peer-reviewed journals, that is, journals that only print articles after having some number of other experts review them. That's certainly not a bad idea, but plenty of articles in such journals are contradicted by other articles in equally responsible journals or have otherwise been proven to be wrong. (See, for example, https://www.scientificamerican.com/article/an-epidemic-of-false-claims/)
If you're talking about straightforward facts that are not particularly controversial -- like the date Donald Trump was born in your example -- if you can find two or three sources that agree, it's likely true. If you really wanted to be diligent you could search for a primary source document, like a birth certificate.
But if you're talking about something that is controversial or emotionally charged -- like whether Donald Trump's tax plan is good or bad for the economy -- you're going to find contradictory information from different sources. Even on purely factual questions, not "is it good?" but "how much will the taxes of the average American go up or down?", different sources will likely give totally different numbers. People will have different assumptions, calculate things differently, etc.
I've had a number of times that I've seen a story in the news that said "recent study proves X", and where I was interested enough to look up the original study and found that it proved nothing of the kind.
Heck, I once ran for a minor local office. A newspaper reporter interviewed me and then printed a story about what I said. He reported that I was in favor of a proposed law that he described. Except ... he never asked me about that law in the interview, I had never heard of it before reading in the paper that I was for it, and in fact if his description of the law was accurate I would have been against it. (Of course his description of the law may have been just as inaccurate as his description of my position on it.) That little incident has made me suspicious of anything I've heard in the news since. How often are famous people misquoted? Whether by mistake or bias.
So how can you tell what's true?
Is it something straightforward and non-controversial? If someone tells me what the zip code of his home town is, he probably knows and it's unlikely he has a reason to lie.
Is the speaker likely to know? Like if I find a zip code on the postal service web site, well they should know. If the postal service web site has a description of a new commemorative stamp that makes comments about history ... maybe they know and maybe they don't.
Do multiple sources agree? If every source you can find on a question agrees, odds are its true. Not necessarily, of course. They could all be getting their information, directly or indirectly, from the same inaccurate source.
Like #3, but especially: Do people on both sides of a controversial issue agree? Like if both the National Rifle Association and Handgun Control Inc agree on some claimed fact about gun violence, odds are it's true. If it was a lie being pushed by one side, you'd expect the other to be calling them out on it.
Has the source been generally reliable in the past? If someone's been convicted of fraud and libel 20 times in the past, I'm not going to take his latest revelations at face value. There's the catch here that what one person considers a reliable source, someone else might think is totally biased. Ask conservatives and liberals for their opinions about the New York Times and Fox News.
From there it all depends on how much work you are willing to do. I've had a few occasions where I've seen a story in the news declaring "recent study proves X", and I've taken the trouble to actually get a copy of the study, and found that it proved no such thing. If the conclusions of the study are key to what you're writing about, you probably should read the original study. If it's a minor point along the way, how much work are you willing to do to validate one stray statistic? Similarly, I've had a few occasions where I wanted to make a point about history and so I've gone to primary sources and read what the original ancient writers actually said. But again, that can be a lot of work. Is it worth it?