Some equity notes

Note: There is really no point to this post. I just wrote it up because there was a situation I was surprised about after doing an analysis. I tend to remember things better when I write them out.

I think that as I've recently started devoting a portion of my playing time to short stacking (to diversify the income streams), I'm starting to spend more time thinking about preflop equity situations. I never seriously put a lot of effort into developing my SNG skills, and guessing vs. calculating ICM numbers is surely more non-intuitive. However, I think that while shortstacking, I'll be running into far more multiway preflop equity scenarios than in an SNG.

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So I'm shortstacking small stakes NL tonight when a simple hand came up:

3-4 limpers, Hero jams for 20xbb with JJ and gets called in 3 spots. The respective calling hands are QJs, AKo, and 75o. All callers have Hero covered.

I was curious about my equity in this situation, so I ran poker stove.
JJ - 24.385% or 19.5bb
QJs- 23.926% or 19.1bb
AKo - 34.325% or 27.5bb
75o - 17.364% or 13.9bb

Unfortunately, it turns out that the middle pair (JJ) is losing about 1/2 of a bb in Sklansky bucks in this type of situation. Yuck!

My immediate, but incorrect, feeling was that middle pair's equity was hurt by the over-overcall.
However, here is the 3-way equity:
JJ - 33.391% or 20.0bb
QJs - 26.164% or 15.7bb
AKo - 40.445% or 24.3bb

As you can see, middle pair's equity is almost unchanged by 75o's over-overcall (but variance increases by about 25%). The other two hands benefit almost equally by 75's awful call. (Although QJs gains just slightly more, which is not surprising since it has more drawing potential).