Especially in a fast moving crisis, official sites cannot always keep up with rapidly evolving information.
Sources: where are sites getting their information? (Be very suspicious of any site that doesn't tell you where the info is coming from.)
Clear explanations of non-sourced material. If they aren't getting information from another source, how was the accuracy of the information determined?
Agreement with official sources: when information is displayed that could/should come from an official source, is that displayed accurately? Be careful with this one, however, because a common technique in persuasion is to "salt" an argument with demonstrable truths, so that you are primed to believe everything.
Transparency: Is it clear what information coming from where and is information from different sources (including non-sourced materials) clearly distinguished?
Here are some examples of "non-official" sources of information and how these might be evaluated:
Forbes is a reputable news sources, but not one specializing in public health. Good: they reference the CDC, HHS, the Harvard Business Review, and the New York City Mayor's Office, all good sources of reliable information. Bad: the article itself is demonstrably an opinion or commentary, but the website does not label it as such, nor distinguish the "official" sources from the more opinion based sources. Opinion sources are very good for relating lived experiences, and, well, opinions, but they should not be the sole source of factual information if that information is available elsewhere. Lived experiences are a very important source of information but are not always generalizable (remember the caveat from the autism community: "If you've met one person with autism, you've met one person with autism.")
This dataset is an attempt to collate state health reporting data on the coronavirus spread. This work is not yet being done (see the history and explanation document. This page is sourcing from official state web pages (note: not all states have reportable data.) Methodology is transparent. This is a good summary document that fills a gap in the information stream, though if someone wants to cite official numbers for a particular state, they should go to the state's website.