One of the best things about the Opponent Strength Index – which is 60 percent of the NJSIAA’s UPR formula for playoff qualification, is that we can have an idea going into a season how challenging a team’s schedule is.
While Strength Index changes every game, most teams will see little overall change to their schedule, as a typical year would see some teams go up, some go down, and some stay pretty close to where they began the year.
We don’t have that luxury with power points, because they’re not based in any way on the previous season. We don’t know how many wins a team will have until the end. And with Group Points no longer a factor in power points, it’s even less reliable.
So, as we do every year, we take a look at how many wins we think every Big Central team needs to qualify for the playoffs.
How do we do it? The methodology is fairly simple.
We figure out what the maximum OSI is that a team could get, assuming the won all their games, and the lowest they could get, assuming they go winless. We divide that by the number of games on the schedule to find out an average of how many points each game is worth.
Using round numbers, here’s an example: Team A plays eight games against teams that all have the same SI value of 80.
If Team A goes 8-0, they would have an OSI of 80, getting 100 percent of the SI value of each team they beat. (Yes, this number will be different by the end of the year, but for our purposes let’s say it stays the same; some teams went up, some down, and it balanced out.)
If Team A goes 0-8, they would have an OSI of 40, getting 50 percent of the SI value of each team they lost to. (Let’s not get into mutlipliers.)
If Team A went 4-4, they would have an OSI of 60. They would get the full 80 points for the four teams they beat (80 x 4 = 320) and half the 80 points for the four teams they lost to (40 x 4 = 160). That’s a total of 480 points, averaged out over 8 games, giving them an OSI of 60.
So that means each game is worth about 5 points on average. Inotherwords, going 8-0 means an SI of 80. A 7-1 record would get you an OSI of 75, 6-2 would get you a 70, 5-3 would get you an OSI of 65, right back to Team A going 4-4 and getting a 60 OSI, and so on.
Once we find the per game value, we need to find the minimum OSI to make the playoffs. It’s not a set number, but it varies by supersection. We look at the highest OSI team to miss the top 16 cutoff, then find the next team higher than that which qualified.
For example, last year in South 2, the lowest OSI team to qualify was Spotswood at No. 16 with a 37.78 OSI. But, Delran missed the playoffs, finishing 17th with a 41.7 OSI. So, we have to find the next team higher than that which qualified; that was Middle Township at a 42.27 OSI. So we would say that no one at 42.27 OSI or higher missed the Top 16 in South 2 in 2023..
Since these numbers can vary from year to year – South 2 had a minimum OSI of under 40 the previous three years – we’re taking an average of the last four playoff seasons, which are all we have to work on. (Remember, there were no playoffs in 2020, and the 2019 playoffs, the first to use OSI, were based on the Born Power Index formula, which was slightly different, so we won’t consider that accurate data.) That average is South 2 is 39.42, so we say if you can reach a 39.42 OSI or higher, you should be in the playoffs.
That said, here are the “minimum OSI” values teams would need to make the playoffs in 2024, based on a four-year average:
- North 5: 40.18
- South 5: 42.44
- North 4: 43.03
- South 4: 42.91
- North 3: 43.46
- South 3: 42.32
- North 2: 40.63
- South 2: 39.42
- North 1: 36.96
- South 1: 36.20
With that data in hand, we can predict how many wins it would take a team to get into the playoffs. We call them “steps,” and we assign all Big Central teams two numbers: the first is to just get over the minimum, and the second is a “full step” over.
For example, if the minimum OSI is 42, and four wins gets a team a 43 OSI, we would say they need four wins to get in, and going one full step over, five should make them a lock.
We have done very well at this in the past, and it’s not because we’re better at math than everyone else, or even calculus. We believe it’s because Strength Index, and OSI, are fairly accurate descriptors of a team’s quality.
Each year, after the cutoff, we look back at our projections. If we said Team A needed four wins to make the playoffs, if they won four or more and got in, we got it right. If they won three or fewer and didn’t qualify, we were also right. But if they won six and didn’t get in, or won three and mad it, we were wrong.
There are a few ways this could go wrong. For example, we don’t count if a team made the playoffs due to a disqualification ahead of them, or wins a tiebreaker. Those don’t have to do with OSI, rather they have to do with NJSIAA formula safeguards. So if we said a team would miss with three wins, and they finished 17, but got in the playoffs because some team in the top 16 had a disqualification, we weren’t wrong – they just got lucky.
But sometimes, everything doesn’t balance out. Take Voorhees, which finished last year 7-4, and was 6-3 at the cutoff, but didn’t make the playoffs. Through no fault of their own, their potential OSI tumbled throughout the year.
Why did they miss? To start, 2022 sectional champion North Hunterdon went from a two-loss team to a winless team, and their SI plummeted from 76.41 to 42.32, after graduating virtually every key player and having a new head coach.
Three of Voorhees’ wins came against North Hunterdon, JFK and South River, all winless. The others came against South Plainfield (4 wins), Bound Brook (2 wins) and North Plainfield (1 win). They beat one playoff team, and lost to the three others on their schedule: Somerville, Delaware Valley, and Bernards.
In three prior seasons of projections, Central Jersey Sports Radio’s projections have had a whopping 95% success rate. That includes going 54 for 57 last year, 55 of 57 in 2022, and 55 of 58 in 2021.
In those three years, our all-time record stands at 164 out of 172 correct in a three-year span.
Here’s the list of all 57 Big Central Conference public schools (the non-publics are seeded differently, by committee) along with their playoff supersection, target OSI, and their minimum wins needed, plus one step over to make them a “lock”:
One might look at this list and wonder why, for example, Ridge and Rahway, both in the North Group 4 supersection, have different win requirements. After all, they’re in the same section together.
It turns out, Ridge has a much more difficult schedule than Rahway, based on the SI value of their opponents.
The Red Devils – if the SI values of their opponents average out to the same they are now – could go as high as a 69.47 OSI if they went 8-0. But the Indians would have an SI of 57.30 if they went 8-0. Ridge’s schedule features stronger teams, according to the SI.
Since the minimum OSI for North 4 is 43.03, four wins would only get them to a 39.40 OSI. It would take Rahway five wins to pass that (46.56) and six to be what we’d consider a “lock,” with a 50.14 OSI. (No one at 50 or above finished lower than 11th last year, for example.)
As for Ridge, two wins gets them to 43.42, just a shade over, and three wins gets them to 47.76, which should be good for about 12th place or higher.
The Big Central has moved more to a scheduling and divisional assignment model based on results than group size, though both are still part of their equation. Consider that Group 5 JP Stevens is now in a division with Group 2 schools like Bernards, Delaware Valley and Voorhees and even playing smaller schools like Metuchen. That’s a nod to giving teams not only a schedule they can compete with, but also helping them get in the playoffs.
Overall, our projections indicate that 40 of the 57 public schools in the Big Central have a minimum four wins to make the playoffs. Ten would need at least five wins, six more would need six wins, and only one – North Plainfield – would need seven.
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