Dr. Diandra: Surprises in playoff performance
The first round of playoff performances defied expectations in both good and bad ways.
That is my excuse for why my very first attempt at making predictions was an abject failure. I projected Alex Bowman, William Byron, Chase Briscoe and Austin Dillon would be the first four drivers out of the playoff. Only Dillon failed to move on to the round of 12.
Of course, my algorithm did not account for Kyle Busch having two engine failures in three races. Especially after his not having had a single engine failure in the previous 92 races.
Nor did the algorithm predict Kevin Harvick’s Darlington race being ended by fire.
Or that none of the 16 playoff drivers would win even one of the first three playoff races.
On the positive side, playoff drivers took 11 out of 15 possible top-fives (73%), and 21 of 30 top-10s (70%.) That’s consistent with a season boasting 19 different winners.
Chase Elliott is the only driver to win more than two races this season. Drivers made the playoffs by finishing well rather than winning of lot of races.
Playoff performance by the numbers
In the table at right, I list drivers in order of points after Bristol — but before re-seeding. Red numbers indicate DNFs.
DNFs played a major role in the first round. Each of the four eliminated drivers had at least one DNF. Harvick and Busch had two each. Both of Busch’s DNFs and one of Harvick’s were due to equipment failure.
Only three drivers earned top-10 finishes in all three playoff races: Christopher Bell, Denny Hamlin and Byron. Two of my predicted eliminations over-performed. And the one driver I expected to dominate the playoffs didn’t.
Relative to the regular season
Excluding equipment failures and crashes, one expects most drivers to perform, on average, at about the same level they ran during the regular season. That mostly didn’t happen.
In the first two elimination rounds, top 10s are enough to stay in the game. So that’s the metric I’ll focus on here.
The graph below compares drivers’ top-10 finish percentage in the first three playoff races to the same metric from the regular season.
Each arrow starts at the driver’s regular-season average and travels to his playoff average. Blue indicates playoff performance better than the regular season and red indicates the opposite.
Six drivers performed better than their regular-season averages would suggest.
Byron entered the playoffs seeded 10th with only five top-10 finishes in the regular season. With three top-10s in the first round of the playoffs, he earned the second-most points of any driver in the round of 16.
Hamlin had the second-largest improvement with two second-place finishes and a ninth. That continues his season-long trend of trying to overcome a slow start.
Bell’s 53.8% top-10 rate for the regular season doesn’t give him much room to improve. But he did. He’s also the only driver with three top-five playoff finishes.
Bowman, whose crew chief, Greg Ives, will retire at the end of this season, increased from 38.5% to 66.6% top-10 finishes.
“I think we are super motivated,” Bowman said, “because its Greg’s last 10 races with me and we want to end on a high note. We know the summer doesn’t matter anymore, our troubles, and it’s a good reset for us going into the playoffs.”
The biggest surprise, perhaps, was Elliott. He has the most top-10 finishes of any driver with 18. But only one came from the first playoff round.
Driver finishes rise and fall throughout a season. The ups and downs are even larger this year because of the new Next Gen car. For that reason, it’s worth comparing playoff performance not only to the entire regular-season average, but also to just the last five regular-season races.
The arrows on the next plot start at the top-10 rate for each driver’s last five regular-season races and travel to their playoff rate.
Seven drivers improved relative to their last five regular-season races -- the six from before, plus Daniel Suárez. Suárez rose from 20% to 33.3%. That’s typical of a season that has been fairly consistent, but not at a level that will take him to the final four.
Byron’s turnaround is even more impressive in view of his having zero top-10 finishes in the last five races of the regular season.
“I think we had a lot of really good tracks in the beginning of the year,” Byron said. “As we started to chase some speed and chase some things, we got off a little bit throughout the summer.”
He believes the team has returned to where it needs to be.
“We know what works; we know what doesn’t work,” Byron said. “We definitely know what doesn’t work after the last month or so, so that’s a good thing.”
Joey Logano has the largest downward trend relative to the last five races, going from a 80.0% top-10 rate to 33.3%.
This graph shows Elliott’s playoff decline to be a trend continuing from the end of the regular season. That might be good news for the other drivers struggling to catch up with him.
Scoring and re-seeding
The table below summarizes points and playoff points earned during the three playoff races and each drivers’ final score before re-seeding. The lineup looks quite different than it did going into this round of three races.
But that’s before re-seeding.
I hadn’t appreciated playoff points until I did the math. Each driver moving on to the round of 12 gets 3000 points, plus their total playoff points.
Because none of these drivers won a race, only five of the 21 playoff points available in the last three races impact the new standings. Bell won two stages; Byron, Bowman and Busch one each.
So we’re mostly back to where we were leaving Daytona.
Ryan Blaney fell a spot. Byron’s dramatic turnaround didn’t impact his playoff standing. Most of Bowman’s move up the charts is due to eliminating the drivers originally ranked seventh, ninth and 11th.
The current standings reflect NASCAR’s eternal struggle between winning and consistency. On the one hand, I understand the desire to mimic other sports’ playoffs and not let the results of the last round impact the next. But carrying over regular-season playoff points means that Elliott returns to P1 despite having earned fewer points in the three playoff races than seven of the 16 drivers.
That’s why Bell, who earned almost twice as many points as Elliott and won two stages, ties for sixth place with Hamlin and Blaney. Elliott goes from 40 points behind Bell to 27 points ahead of him.
If Bell or any of the other remaining drivers wants to challenge Elliott, even top-five finishes won’t be enough.
In these playoffs, performance isn’t enough. You have to win.