Understanding the MIAA Power Rankings (with AI Help)

The MIAA Power Rankings blend Margin of Victory (MOV) and Strength of Schedule (SOS). 

What's vital is their description of "iterative." The SOS averages the rankings of all previous opponents up to the most recent. Here's where ChatGPT Plus steps in (lightly edited).

MOV is easy. If "sets won minus sets lost" is 20 and you played 10 matches, then 20/10 equal MOV of 2. Currently, Melrose is +13/9 = 1.4444. 

SOS is different. The most important passage is essentially this: any game played across the state can affect the ratings of any and all teams, even if only by a few decimal places. That is a more than simply saying SOS is iterative.

For your Melrose example, our earlier calculation after Newburyport was only a first-order estimate. We treated Newburyport’s 4.1719 rating as frozen. The actual MIAA calculation does not. If Newburyport subsequently beats good teams, its rating rises, which raises Melrose’s opponent-rating component retroactively. If Newburyport’s future results disappoint, Melrose’s benefit from that win can shrink. And the same thing happens with every opponent already played.

The MIAA’s published ranking sheets reinforce this definition directly: they label “OPP. RATING” as the average of a team’s opponents’ overall ratings, rather than win percentage or a static schedule score.

This produces an important implication that is easy to miss:

You don't merely root for the teams you are about to play. After you play them, you keep rooting for them.

A win over a 4.2 opponent is not permanently worth “4.2 SOS points.” That opponent might become a 6.0 team—or a 1.5 team—and your rating migrates with it. Personal calculations become estimates. 

It also explains why early-season MIAA rankings can look peculiar. With relatively few games played, one opponent's rating can move sharply, and because the system is interconnected, those changes propagate. As the schedule fills in, the network acquires more data and ratings generally become more stable.

And this is why the new ML12 schedule structure matters even more. Fewer games against chronically weak teams does not merely avoid one low SOS input on the date of the match. Every opponent remain attached to your rating for the rest of the season. 

In shorthand:

MOV is mostly history.
SOS remains alive.

As Coach Scott Celli might say, "You play the schedule." Play well and wish our previous opponents well.