There are a plethora of published market research reports out there, but some of these reports aren’t from credible publishers. Here are some red flags for me.
I look at the pagination of the table of contents and noticed that there isn’t much content devoted to a topic or competitor. Basic I know, but if these aspects are the reason for buying the report, then maybe rethink things. For me, this lack of space often corresponds with just contact details supplied or very generic information. In this case, ask for a sample from the publisher to check the content. You can then appraise the sample to reassure yourself about the standard of English used as well. One sample I requested had such a low level of business English that it was intelligible.
With markets like medical devices, for instance, there are many different configurations of what is counted or researched in terms of functionality or size. Another trap I have come across is when studying the markets of mechanical devices and how they are powered eg. electric, battery, petrol, or diesel. Researchers often don’t state exactly what they are counting and for what market segment it is meaningful to.
Cookie cutter reports follow the same prescriptive outline - I can spot one of those a mile off. They are heavy on historical detail, the numbers are dated, and there’s nothing future-oriented. There’s little value in these often expensive market research reports IMHO. Foresight is always going to be better than hindsight to get insight and to protect market share. The ROI of you (or me!) spending time doing a recent news search and see what’s going on now is a much better option.