Various studies on the total cost of ownership (TCO) of Windows versus Linux have arrived at vastly different conclusions. How is this possible? The short answer is that if you are abstract enough with your goals and methodology, are selective with the costs that you include, and ask the right questions, then you can arrive at any conclusion you want.
Here are some of the things you need to consider as you read a report. First, read the whole report.
A lot of people make decisions based on press releases or summaries of analyst studies, but these brief sources don't provide enough information. Tedious as it may sometimes be, you must read the whole study with a critical eye in order to determine the relevance of the advice to your organization. In fact, you may need to read the report at least twice in order to judge it properly. Skim it first for a "common sense" test, then delve in with the following issues in mind.