grammar - “Investigation report” vs “Investigative report”

There's an article on the internet written about how to write a report of an investigation.

However, I'm a bit confused of the usage of "investigation" and "investigative" in the article.

The link of the article is here: https://i-sight.com/resources/ultimate-guide-to-writing-investigation-reports/

In that article, they call it "Investigation reports" in the title, but they use "Investigative report" in the body of the article, instead.

I don't know whether this sort of usage is their mistake or it's grammatically correct. If they're absolutely correct, please explain to me the difference between "Investigation report" and "Investigative report".

And a side question, can I use "Investigating report"?

Many thanks.

Answer

For all intents and purpose, 'investigation report' and 'investigative report' should not matter in meaning, especially in the case of your source article, which seems to liberally switch between the two.

But I do perceive the difference.

'Investigation report' is a compound noun. It means the report of an investigation (which you might have made). The report has a neutral tone: you are simply presenting the facts and figures you have uncovered during your investigation.

In 'investigative report', 'report' is modified by the adjective 'investigative', meaning 'intended to examine something carefully'. In this case, the nature of the report becomes more of an argument. It implies that this report carefully examines evidence, argues for an idea, and draws conclusions or presents a theory. Perhaps you might have heard of investigative journalism or investigative reporter whose job is to discover the facts and present it in a manner that convinces the reader.