Playoffs bring new format, RPI to high school football

The playoffs are upon us and Kentucky High School football is about to see its first glimpse of the new and improved post-season tournament system.

The three local teams are in action Friday night. At least one of them--maybe two-- will advance to the next round.

Somerset, who is at 9-1 overall and 2-1 in its four-team district, will be at home on Friday against Danville, a team which it beat 40-21 on October 11.

Pulaski County is 7-3 overall and 3-1 in its 5-team district. The Maroons will play cross-town rival Southwestern. The Warriors are 5-5 overall and 2-2 in the district and ironically handed Pulaski County its only district loss of the 2019 season, winning 15-7 on October 25.

In the past, the football playoffs have begun with teams playing a regional tournament with the top seed from one district playing the bottom seed from the neighbor, and the 2 playing the 3. That much has changed. This year, the format is one of a district tournament. Teams which have played each other less than a month before will see each other again under this format. The number-one team in each district in the state will play the number-four team, with the two-seed playing the three-seed. It is believed that this format insures a meeting of the best teams later in the tournament.

The winner of each district will then go on to play against other districts in the semi-state tournament. Four districts are generally in the south; four are generally in the north. The third round of the playoffs is where these competitions take place. But this year, there is a new twist to the pairings. That twist is called the "Ratings Percentage Index" or RPI.

As each team plays through the regular season, it accumulated a won-loss record. That part is pretty easy for anyone to figure out. The percentage of wins is a factor of the total of wins divided by the total number of games.

But Kentucky has six classes of football teams, arranged roughly by size ranging from very small schools to very large schools numbered Class 1A through Class 6A. The theory (and assumption) is that a larger school will have an advantage on the football field. But teams play teams from higher and lower classes all the time. So, a multiplier, called a game value factor, is applied to each win to help make the calculation. A win over a 1A school would have a value of 1.323, whereas a win over a 6A school would be worth a multiplier of 2.660.

When the season is over, all the numbers are added up and a winning percentage is calculated.

But people who deal with sports statistics are never happy unless they are doing more and more math. So, the RPI system adds two more factors into the equation: The percentage valuation of all of the opponents and the percentage valuation of all their opponents. If you are seriously considering checking the math, you can go to the KHSAA website at khsaa.org and see how the RPI =(WP*WPVAL)+(OWP*OWPVAL)+(OOWP*OOWPVAL) formula works. Oh yes, they then factor these three values roughly a third each.

You don't have to do the math, though. KHSAA has a vast database with thousands of datapoints and the algorithm already set up with the RPI of every participating team in the state. The higher the RPI, the stronger the team is theoretically. That RPI is frozen in place as of the end of the regular season.

Southwestern comes into the playoffs with a .51765 RPI. Theoretically, Pulaski County is stronger with an RPI of .58993.

Somerset finished the regular season with an RPI of .75279.

At the end of Round 2, there will be eight district champions: four from the south and four from the north. The RPI's are used in order to determine who plays who and where. The team with the highest RPI will play the fourth at home. Two will play three at home.

Home field advantage goes to the team with the higher RPI for round 4, after only two teams will remain. Those teams meet on Saturday, December 7 at Kroger Field in Lexington.

So now you have a sketchy, but accurate look at the way the system works on paper. After about 20 years of doing football stats, I can only say that the only sure-fire guarantee is as follows: 100 percent of the high school tournament games are decided on the field and not on paper.

But the stats are fun, anyway. Enjoy the playoffs.

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