Bill James devised the Plexiglas Principle way back in the 1980s. It states that a team which improves in one season will usually decline the next season, and vice versa --- a team which declines in one season will usually improve the next season. This is a general guideline, not a rule or a law; it is true the majority of the time, but not all of the time. The Plexiglas Principle grows stronger the longer a team defies it; if a team improves for two straight years, the team's chances of declining the next season rise significantly. Lastly, there's a caveat about Pythagorean records. James noticed that teams which win more games than projected by their Pythagorean record tend to decline, while teams which win fewer games than projected by their Pythagorean record tend to improve. This is a contributing factor to keep in mind when using the Plexiglas Principle.
I decided to look at the upcoming IBL season from the perspective of the Plexiglas Principle. I omitted Paris and Tokyo because they're tanking; the Plexiglas Principle only applies to teams that are trying to win. So anyway, here are my assessments of the other eight IBL teams, as viewed through the lens of the Plexiglas Principle.
Ljubljana.
The Dragons’ pattern over the past four years has been DOWN, DOWN, UP, UP. Logically, the next step in that sequence would be DOWN. Also note that the Dragons’ win total increased by a whopping 17 games in 2126; the Plexiglas Principle states that a team which improves by that much in one season is almost certain to decline the next season. Lastly, note that the Dragons’ record in 2126 was two games better than the team’s Pythagorean record, and a team which outperforms its Pythagorean record tends to decline the next season. Add it all up and you get the following conclusion:
The Plexiglas Principle projects that the Dragons will win FEWER games in 2127 than they won in 2126.
Karachi.
Win totals of the past five seasons: 60 65 53 80 71.
The Falcons’ pattern over the past four years has been UP, DOWN, UP, DOWN. Logically, the next step in that sequence would be UP. Also note that the Falcons in 2126 underperformed their Pythagorean record by 9 games, an unusually large number; this indicates that their poor record was partly due to bad luck. So the conclusion seems clear:
The Plexiglas Principle projects that the Falcons will win MORE games in 2127 than they won in 2126.
Cairo.
Win totals of the past five seasons: 69 90 92 97 101.
The Pharaohs’ pattern over the past four years has been UP, UP, UP, UP. This is an absolutely historic run. The Plexiglas Principle states that it is unusual for a team to move in the same direction for two straight years. It is very unusual for a team to move in the same direction for three years, and it is virtually unheard of for a team to move in the same direction for four straight years. The Pharaohs’ record has improved for four straight years and is therefore way overdue to make a turn in the opposite direction. So:
The Plexiglas Principle projects that the Pharaohs will win FEWER games in 2127 than they won in 2126.
Rome.
Win totals of the past five seasons: 75 77 80 70 81.
The Generals’ pattern over the past four years has been UP, UP, DOWN, UP. This alone would tend to indicate that they are due to decline somewhat in 2127. To bolster that sentiment, note that the Generals improved in 2126 by 11 games; teams which improve by such a large amount in one season tend to take a step backward the following season. Lastly, the Generals of 2126 outperformed their Pythagorean record by three games. The markers are all in agreement, and they all point to the same conclusion:
The Plexiglas Principle projects that the Generals will win FEWER games in 2127 than they won in 2126.
Manila.
Win totals of the past five seasons: 80 86 73 90 85.
The Folders’ pattern over the past four years has been UP, DOWN, UP, DOWN. This indicates that they should probably improve in 2127. However, in 2126 they outperformed their Pythagorean record by three games; that indicates that they should decline in 2127. So in this case the markers are not in agreement; they are not pointing in the same direction. Still, since the team’s record declined by five games while its Pythagorean record was only three games off, the weight of the evidence indicates improvement. It’s a coin toss, really, but:
The Plexiglas Principle projects that the Folders will win MORE games in 2127 than they won in 2126.
Melbourne.
Win totals of the past five seasons: 71 71 74 74 82.
The Meteors’ pattern over the past four years has been SAME, UP, SAME, UP. The team’s record hasn’t declined since 2122; that’s unusual. A decline therefore seems overdue. Also note that the team improved by 8 games in 2126; that’s a pretty big jump, indicating that a downturn is probable. Lastly, the Meteors outperformed their Pythagorean record in 2126 by four games, which indicates that they were somewhat lucky. All of the markers are pointing to the same conclusion:
The Plexiglas Principle projects that the Meteors will win FEWER games in 2127 than they won in 2126.
Mumbai.
Win totals of the past five seasons: 101 97 102 104 102.
The Cobras’ pattern over the past four years has been DOWN, UP, UP, DOWN. It’s not a clear pattern; moreover, the win totals haven’t fluctuated much at all. Thus it’s very difficult to pinpoint a direction for this team in the coming season. Consulting the Pythagorean record is no help; the 2126 Cobras exceeded their Pythagorean record by only one game. In short, the markers point in different directions, and none of the markers point very strongly in ANY direction. My best guess is that, due to the fact that the Cobras improved for two seasons and then declined for only one, mixed in with the fact that they slightly exceeded their Pythagorean projection last year:
The Plexiglas Principle projects that the Cobras will win FEWER games in 2127 than they won in 2126.
Black Forest.
Win totals of the past five seasons: 80 88 107 98 76.
The Foxes’ pattern over the past four years has been UP, UP, DOWN, DOWN. This would tend to indicate that the team is due to increase its win total in 2127. Bolstering that conclusion is the fact that the Foxes’ win total dropped by an utterly incredible 22 games in 2126. That’s the largest single-season drop in franchise history, and probably the largest single-season drop any WBA team has ever experienced if you exclude teams which were purposely tanking. A team which declines this precipitously is almost guaranteed to bounce back to some extent the following season. Also note that the 2126 Foxes won six fewer games than their Pythagorean record would indicate. All of the markers are therefore pointing very strongly to the following conclusion:
The Plexiglas Principle projects that the Foxes will win MORE games in 2127 than they won in 2126.
It'll be interesting to see how these projections pan out. I plan to return to this post at the end of the 2127 season for a followup.
I didn't bother with the ABL because who cares.
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