Ranking Stability – Divisional Round

Tom here with the Beatpaths ranking stability. Last week, the results of only four wildcard round games, instead of the normal 16, nevertheless produced significant changes in the rankings. This week, the four divisional round games produced the opposite results: only three pairs of teams switch places. The total change in ranks was a mere six.

Stability Divisional Round

Because of the all the redundant beatpaths built into the rankings at this point in the season, it’s not clear to me that the results of the final three games can produce the kinds of big shifts we saw during the regular season or even as a result of the wildcard round. We’ll see.

While it might strike some as overly geeky to analyze system stability for Beatpaths’ rankings, I’ve decided to outgeek myself, pushing into a second-order stability analysis. Each week’s stability chart includes a logarithmic trendline superimposed over the data, indicating the overall direction in which the rankings were headed each week as new data was included. On a lark, I decided to see how consistent the trendlines were, from week to week. Below are the charts from Week 14 through the Wildcard Round, superimposed upon one another.

Trendline Overlay Weeks 14-18

I stretched each chart until the axes lined up. As you can see, the trendlines show remarkable consistency from week-to-week despite pretty significant ups and downs in the stability of the rankings. I added red guidelines indicating the range of the trendlines. The trendline terminus stays within the upper-60s each week.

What does this mean? Not only does the trendline indicate that the system’s rankings were getting more stable overall each week, but that the trend toward greater ranking stability itself remained stable. Just as the retroactive pick record seems to lend strong confirmation of the increasing accuracy of the Beatpaths model over time, I think the trendline consistency illustrated above likewise gives us a strong confirmation of 1) the Beatpaths system’s internal coherency, and 2) its ability to interpret and give meaning to each week’s new results within a season-long strength-of-schedule context.

Leave a Reply

Your email address will not be published. Required fields are marked *