To me the eternal search for clutch is a colossal waste of time.
If hitters are clutch, so are pitchers. For that matter, so are managers who can rise to the occasion and effect outcomes with better in-game decisions. Heck, even umps can be clutch, I suppose. All of that effects the mystical clutch equation and the outcomes clutch allegedly produces.
Then you have to factor in outside factors like weather. Was that clutch home run the result of steely batter's skill or lucky wind drafts through the stadium? What that clutch shot up the middle the result of highly tuned reflexes or the short stop misjudging the ball because of glare? Was that clutch strike out the result of a veteran nerves, or a batter who had the stomach flu the week before and hadn't gotten his timing back yet?
So once you wade through that swamp of factors you have to ask yourself, "who cares?". Are you really going to turn down the services of Alex Rodriguez all season because of some goofy notion that he isn't clutch? Are you really going to pencil in Mr. .245 hitter all year because he might come through in a clutch moment in the last game of the season?
Clutch does nothing, or at least very little, to effect decision making regarding baseball games. Therefore, who cares?
I don't doubt that some people preform well under stress while others crumble. I've espoused that here before. I just think it's so murky, so undefined, and so minor to the outcome of baseball games that it's not worth the time to attempt to ferret out the information.