FanGraphs Power Rankings: August 5–18

If it’s parity you’re looking for, consider this: 10 of the top 11 teams in these rankings are separated by just 4.5 games in the major league standings, and the odd team out has been the hottest ballclub in baseball over the last two weeks. While no team is currently on pace to win 100 games, the bunching in the standings should make for some very exciting playoff races down the stretch.
This season, we’ve revamped our power rankings. The old model wasn’t very reactive to the ups and downs of any given team’s performance throughout the season, and by September, it was giving far too much weight to a team’s full body of work without taking into account how the club had changed, improved, or declined since March. That’s why we’ve decided to build our power rankings model using a modified Elo rating system. If you’re familiar with chess rankings or FiveThirtyEight’s defunct sports section, you’ll know that Elo is an elegant solution that measures teams’ relative strength and is very reactive to recent performance.
To avoid overweighting recent results during the season, we weigh each team’s raw Elo rank using our coin flip playoff odds (specifically, we regress the playoff odds by 50% and weigh those against the raw Elo ranking, increasing in weight as the season progresses to a maximum of 25%). As the best and worst teams sort themselves out throughout the season, they’ll filter to the top and bottom of the rankings, while the exercise will remain reactive to hot streaks or cold snaps.
First up are the full rankings, presented in a sortable table. Below that, I’ve grouped the teams into tiers with comments on a handful of clubs. You’ll notice that the official ordinal rankings don’t always match the tiers — I’ve taken some editorial liberties when grouping teams together — but generally, the ordering is consistent. One thing to note: The playoff odds listed in the tables below are our standard Depth Charts odds, not the coin flip odds that are used in the ranking formula. Read the rest of this entry »







