Note: Edited to reflect a more accurate coefficient. The net result is still crazy.
I commented in today's Game Chart thread that I was quite interested in the combined effects of the Mariners struggling offense and awesome run prevention, and I wanted to follow up on that. We've discussed at length around these parts the effects of various presences on the roster and their effect on the outcomes of games. The most common and handy conversion factor for runs to wins is about 10:1. For every additional 10 runs of value produced in any phase of the game by a team, you'd expect an incremental win. For instance, I took a look at the effects of some of Don Wakamatsu's decision making and the likely decrease in wins we should expect based on those moves. To get my results, I used the standard 10 run/win conversion. However, this conversion rate is based off of the average case over the course of a season. The Mariners haven't been an average case.
To date, the Mariners have scored 121 runs and allowed 144 runs over their 37 games. Since the run to win conversion comes from the Pythagorean expectation formula, it's a pretty simple task to plug in our current numbers. Based on their current run numbers, the Mariners should have won 15.3 games. Fine. I'm not interested so much in that. What I'm interested in is the change in win value predicted by an increase in one run, which comes out to .136 wins. Therefore, the run/win conversion rate for the Mariners as they stand right now is 7.4, a far cry from 10. The run environment created by our zany Mariners creates an increase in Win Leverage (10 / 7.4) of 135%. Previous sentence bolded for your pleasure.
This is really important. Every upgrade or downgrade at any position is magnified by ~1.35 times the win value. Of course, making a change at any position that alters the team's run profile will also adjust the Win Leverage going forward, but that's to deal with later. If you've watched games with the gut feeling that runs are just more important in contests involving Seattle than they are for other teams, you're correct. Right now, any move made by the Mariners has a third more impact that it would for an average team. Wrap your noodles around that.