Readers should be able to see where the information in a news report came from.
Some things don’t need a source. If something is common knowledge or if it has been widely reported on and is in the mainstream, it probably doesn’t need a source.
However, if your reader could conceivably doubt what you wrote, you should include a source so they can check up on where you got the information.
If information is controversial, you should include a source for anything you write that could be considered opinion or unfounded.
If you are quoting a newsmaker or expert, you should include a link to the source from which you drew the quotes, or mention in the article how the quotes were obtained.
If you are using statistics or other empirical information, you should include the source of that information.
Obviously, some news reports require sources more than others. There are articles that do not require sources. Original reporting does not always require sources because the journalist is reporting first-hand. More controversial subjects often require more sources.
Do not:
- Do not link to a single source more than once. Once is enough. (There are exceptions.)
- Do not use Wikipedia as a source. Wikipedia cannot be used as a news source. If you want to use a piece of information from Wikipedia, find another source for that piece of information. You can also follow Wikipedia’s citation to their source and use that, so long as it holds up.