When critically analyzing a report, make sure you read it start to finish. Often a nice trick is to start at the back and read all the addendums before you read the actual report. This is often where the limitations or constraints are placed. And knowing these before you interpret the report is helpful.
Print it out, get a cup of coffee, get a pen, go to a quiet place. Read it through. Write notes.
What surprised you, what was obvious, what were the arising questions?
What were you expecting? Are there any gaps in this report? Is it sufficient? Was it too much? These are all questions to ask in analyzing a report.
Finally, did it do its job? Did the report help you make a business decision, that you couldn’t have before? For that is the ultimate test of a report. It’s not just data, it’s not just a story, it is the interweaving that leaves the intended audience with the knowledge they need.