I should warn you now that nothing that follows is in any way groundbreaking, and the bulk of it is only mildly illuminating. This quick research was done mainly to satiate my own curiosity, and you're free to click elsewhere before reading on. I promise I won't be offended.
In case you're still here, let me explain - an idea came to me last night in the shower. I get more baseball-writing ideas in the shower than you would probably like to know. It was a very simple idea. I remembered hearing during a game I was watching that some batter usually "makes his swings count," and I wondered about that. I thought that I would run some calculations and figure out which batters turn the highest and the lowest percentages of their swings into hits.
So that's just what I set out to investigate today. Unfortunately, I couldn't track down the required data. I couldn't find pitch or swing data for hitters, which stopped me at the start. However, I could find that data for pitchers. For some reason it's more readily available for the latter than the former. So, for me, this was a simple on-the-fly adjustment. Instead of researching which hitters make their swings count, I researched which pitchers allow the most and least swings against them to count.
I went back to 2002, which is as far as I could take the Fangraphs data. I then set a minimum of 400 innings pitched to weed out any sample size noise. This left me with a group of 329 pitchers, some of them still playing, some of them retired, and some of them in between. Below, please find the top and bottom ten in Hits/Swing%.
Nothing entirely shocking here. Former Twins starter Joe Mays leads the way. Over the span of time examined, Mays allowed 553 hits on 3,123 swings. Behind Mays, you can find nine other clones of Joe Mays.
Congratulations! You made it through the data part. Here, our leader is another Twin - Joe Nathan, who has allowed 345 hits on 4,064 swings. That's good for a rate that's less than half of what Mays posted. This part of the leaderboard is dominated by relievers, and I probably should have separated them from the starters, but at least Chris Young checks in there at #320. Young's the representative starter, as he's been quite effective when healthy.
So that's it. My curiosity has been satiated, at least in part. If you're curious about the rest of the data, you can view the entire spreadsheet here. And hopefully some day I'm able to repeat this with hitters, which I would quite like to see.