In fixing English, the hardest part is a text which is only slightly wrong.
Combine that with a significant and growing familiarity with certain kinds of mistakes, and the mistakes start looking not so wrong. Nobody will really misunderstand the sentence, but still, it's just not right. It's not the way a real anglophone would write.
OMG, does that mean I'm not a real anglophone any more?
A study on...
A study of...
It's like taking a wrong turn to go someplace, then the next time taking the same wrong turn, and on further trips the wrong way looks so familiar you keep taking it!
Then of course the content is not exactly my usual domain. It's all fuzzy, and slippery. (fuzzy and slippery at the same time?? that's permitted; that would be algae growing underwater.) It's appropriate in a way that a discussion of relaxation techniques would resort to massaging the data. In one place we're going to group together similar studies in order to get a more meaningful result: we've got two papers on hypnosis that set up a model, which is used by 'a whole set' of other studies, and we permit ourselves to add studies -plural- that use guided imagery. Add that up and it somes to a minimum of six papers, perhaps many more. Mmm. A minimum of five, since technically one is a set even if it would be strange here to mean it that way. But whatever. The actual total is four.
It's hard to build a field of study with just four bricks.
And they're kind of squishy bricks.
I do exaggerate. It's fun to exaggerate in blogland. Or is it nitpicking? Yes, nitpicking. Four is not an exaggeration; it's four.
Besides, the point is to show that there is in fact a crying dearth of data, that more work needs to be done. I guess. And from that angle, well, four is good for the cause.