It was bound to happen-a study about studies. It's really just common sense. If you notice how much of what passes itself off as 'science' just happens to validate some leftist group's political agenda, like global warming, you start to wonder about the validity of the study. Political correctness is torturing history exactly the same way. The earth is flat and don't you dare question it. Especially on a college campus.
A good friend of mine used to work as a lab tech for animal experiments, or as he puts it, he "tortured animals for a living."
He tells the most appalling stories about how studies were designed to avoid finding what they didn't want to find.
The phenomenon you describe is unfortunately not at all limited to those with a leftist agenda. Money can also do a good job of motivating a scientist to find a way to find what he, or his backers, want found.