So, as we were puzzling over the mathematically-inexplicable suckitude of the Nats yesterday, commenter Graysnail wondered out loud what the Nats' situational run expectancy looked like. Don't worry, ye stats-averse, this isn't as complex as the name sounds. It's the number of runs you score (on average) starting from a given number of outs and men on base. For example, the average team scores 2.27 runs before ending the inning if they have the bases loaded and no outs. The run expectancy with bases-loaded, no outs is 2.27. Here is Baseball Prospectus' Run Expectancy for the 2009 season so far (including both AL and NL teams):
| On Base | no out | 1 out | 2 out |
| --- | 0.52 | 0.28 | 0.10 |
| 1-- | 0.88 | 0.55 | 0.23 |
| -2- | 1.12 | 0.69 | 0.31 |
| --3 | 1.30 | 0.96 | 0.40 |
| 12- | 1.48 | 0.93 | 0.46 |
| 1-3 | 1.77 | 1.19 | 0.57 |
| -23 | 2.01 | 1.42 | 0.59 |
| 123 | 2.27 | 1.57 | 0.78 |
After a big data dump from baseball-reference and a bit of SQL, I'll give you the same for the Nats so far this season after the jump:
| On Base | no out | 1 out | 2 out |
| --- | 0.47 | 0.25 | 0.08 |
| 1-- | 0.77 | 0.42 | 0.14 |
| -2- | 1.10 | 0.67 | 0.30 |
| --3 | 0.33 | 0.81 | 0.40 |
| 12- | 1.69 | 0.74 | 0.37 |
| 1-3 | 2.00 | 0.97 | 0.20 |
| -23 | 1.90 | 1.44 | 0.17 |
| 123 | 1.89 | 1.29 | 0.47 |
Before you scream too loudly about the inability to score from 3rd with no outs, keep in mind that's based on only three instances. The "insufficient stats" problem for some of the no-out cases aside, the bases-loaded failures that are so prominent in our memories seem to be real. The Nats score 0.3 fewer runs than the average team with the bases loaded. Most of the other combinations are fairly close to average (within 0.2 runs), and some are slightly better--runners first-and-second or first-and-third with no outs, for example. The Nats do seem to be consistently below average with multiple men on base and two outs. I'm not sure how much the results of the baseline run expectancy gets skewed from having both AL and NL mixed together, and I might have a go at figuring an NL-only run expectancy if I can get the baseball-reference data hamsters to spin out the data.
So, what does it mean? Aside from "MOAR RUNZ PLZ," I'm not sure--but I thought I'd share with the class.