SOTG MLB Power Rankings 2

by Matthew de Marte – August 8th, 2018

Last month, SOTG introduced its very own power rankings. The power rankings are derived from an algorithm that you can read about HERE – The goal of the rankings were simple: Create a ranking system that does a better job of predicting future success than current methods available to the public. While creating the rankings there were a few metrics I had to establish: weighted Run Differential (wRD) and wRD Win %. In our first edition, the top five teams in baseball were the Astros, Red Sox, Yankees, Cubs, and Braves, respectively. If you need to catch up on how the rankings were calculated, I suggest reading the first power rankings. Let’s take a look at the SOTG MLB Power Rankings entering play on August 8th. Team rankings in the previous edition of the ranking system are in parenthesis below:

Rank Team wRD W-L wRD W% Home wRD Away wRD W-L Win % Luck
1 (1) HOU 78-37 0.678 23 145 73-42 .635 -5
2 (2) BOS 76-38 0.667 66 82 80-34 .702 4
3 (7) LAD 70-44 0.614 39 50 63-51 .553 -7
4 (3) NYY 67-45 0.598 32 39 70-42 .625 3
5 (4) CHC 66-47 0.584 4 60 66-47 .584 0
6 (8) CLE 65-47 0.580 30 25 62-50 .554 -3
7 (6) ARI 65-50 0.565 15 32 63-52 .548 -2
8 (10) MIL 65-51 0.560 29 11 65-51 .560 0
9 (16) OAK 63-51 0.553 -5 35 67-47 .588 4
10 (5) ATL 60-50 0.545 -8 31 61-49 .555 1
11 (9) WSH 61-52 0.540 -2 22 58-55 .513 -3
12 (11) PHI 61-52 0.540 25 -10 64-49 .566 3
13 (15) LAA 62-53 0.539 3 12 57-58 .496 -5
14 (14) PIT 59-55 0.518 -4 3 58-56 .509 -1
15 (18) SF 59-56 0.513 25 -41 57-58 .496 -2
16 (17) STL 58-56 0.509 -30 18 59-55 .518 1
17 (12) TB 57-56 0.504 35 -54 57-56 .504 0
18 (22) COL 56-57 0.496 -25 -4 60-53 .531 4
19 (20) TEX 55-60 0.478 -38 -7 50-65 .435 -5
20 (13) SEA 53-61 0.465 -15 -42 65-49 .570 12
21 (19) CIN 53-61 0.465 -34 -26 50-64 .439 -3
22 (21) TOR 50-62 0.446 -51 -27 51-61 .455 1
23 (23) MIN 49-63 0.438 -34 -57 53-59 .473 4
24 (25) SD 49-66 0.426 -75 -23 45-70 .391 -4
25 (26) MIA 48-67 0.417 -17 -95 47-68 .409 -1
26 (24) NYM 46-65 0.414 -64 -41 46-65 .414 0
27 (27) DET 46-68 0.404 -18 -109 47-67 .412 1
28 (28) BAL 38-75 0.336 -73 -111 34-79 .301 -4
29 (29) CWS 35-78 0.310 -92 -121 41-72 .363 6
30 (30) KC 33-80 0.292 -143 -89 34-79 .301 1

Let’s break down this month’s rankings! I was surprised to see the Astros still clinging to the top spot over the Red Sox. Although there is not much separating them at the top, I expected the Red Sox to take over the top spot, especially sweeping the Yankees this past week. The biggest movers in this edition of the wRD Win % rankings were both from the AL West. The red hot Oakland A’s, who have gone 21-8 since the last rankings, climbed seven spots to enter the top 10, while the Mariners whose wRD Win %has never been very high in the first place fell seven spots to #20. The top 5 remained pretty much the same. The Braves fell out after their recent struggles, while Manny Machado and the Dodgers rose to the number three ranking, surpassing the Cubs as the top team in the National League.

Now we will take a look at how the predictive power of wRD Win % fared since the last rankings.To analyze this, we will look at Win %, Pythagorean Win %, and wRD Win % for the July 2nd power rankings and compare them to teams Win % since then. This will give us a good idea of which measure was the best at predicting team performance over the last month.

The following plot compares teams July 2nd Win % to their Win % from July 2nd through games played on August 7th:

Correlation = .6072219

The following plot compares wRD Win % on July 2nd and teams Win % from July 2nd through games played August 7th:

Correlation = 0.6771952

Unfortunately, this time I was unable to use Pythagorean Win % in this comparison, but I will be able to use it next time. wRD Win % had a correlation of 67.7% to future Win %, while Win % itself had just 60.7% correlation. Meaning wRD Win % was a better indicator of future performance than a teams Win %! I hope you all enjoyed this edition of the SOTG power rankings. As always, reach out to studentsofbaseball@gmail.com if you have any questions!

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