Now that the NJSIAA has released its official starting Strength Index numbers for the 2021 high school football season, who’s the strongest team in the Big Central?
Well, to be honest, not much changed since the end of the 2021 season.
At least at the top, Phillipsburg has the highest 2021 preseason Strength Index in the league, followed by Somerville.
The top five are rounded out by Woodbridge, Union, and Hillside.
Here are the Top 20 teams in the Big Central, along with their state rank:
Strength Index is calculated by taking each the rating of each team in a particular matchup, finding the difference, and seeing how the higher-rated team did. If the higher-rated team wins by more than the difference between the teams, their Strength Index goes up by 1/5 of the difference. If the higher-rated team wins by less than the difference between the teams (or, of course, loses) their Strength index goes down by 1/5 of the difference.
Strength Index is cumulative, and calculated each week, right on through the postseason, whether playoffs or consolation games.
SI values are locked after the final week of play before the state playoff cutoff. Then, for playoff calculation, Opponent Strength Index is used. A team that wins a game gets the full Strength Value of its opponent. A team that loses a game gets half the Strength Value of its opponent.
Teams are rewarded for good sportsmanship under the system because winning by a higher margin drives down the Strength Index of the opponent, meaning the winning team gets fewer OSI points because their value decreased (they got blown out, and are considered weaker).
The OSI is 60 percent of the NJSIAA’s playoff formula, with traditional power points being the other 40 percent.
Typically before a new season starts, team’s SI numbers are “centered” to a midpoint of 60 by one-third. That means a team that has an SI of 90 would be reduced to 80; that 10-point reduction is 1/3 the distance from 90 to 60. The thinking is that helps reduce the “historical impact” of the previous season on the upcoming one.
And in a normal year, this would occur on an annual basis. But, according to Gridiron New Jersey – which handles the NJSIAA’s power points and SI/OSI calculations – the pandemic season changed that. While some teams played nine games, a handful barely got in two or three.
As a result, the NJSIAA opted not to center numbers before the 2020 season, and continue right on through with calculations, almost as if the 2019 and 2020 seasons were one. The numbers were recentered, however, this summer, in preparation for the 2021 season.
Here’s the statewide Top 20 in preseason Strength Index:
Throughout this week, we’ll have a full analysis of the data, including:
- How do the Big Central Divisions stack up against each other? Which is the strongest? Which has the toughest schedules?
- What would the Big Central look like if divisions were determined by Strength Index?
- Who’s got the toughest schedule? Who has the easiest? A look at “playing up or down.”
- Who many wins will get teams in the playoffs? Explaining Piscataway assistant coach John Thompson’s “step” method to find each team’s Magic Number.