Q. How do I determine where an author found the statistics he presents in a report?

Ideally, authors will cite the sources of statistics they present in their work.  In these cases, you can go to the works cited page at the end of the writing and then seek out the cited source to see if the author is citing the source accurately.  This is one of the advantages of using sources from peer-reviewed journals; authors in these journals must document all of their sources.

If an author does not cite the source of statistics presented in a piece of writing, there is no way to determine where they came from.  In situations like this, it would be a good idea to evaluate the source using these criteria.