Friday, 4 September 2026

Are the scrutineers picking on my driver? - Update after the Dutch Grand Prix

For the purposes of this series, the main thing for the Dutch GP was Hadjar missing it due to injury. Lawson moved up to Red Bull, and Tsunoda was temporarily back in whatever Toro Rosso are called this year (I think it's Racing Bulls, I can't keep up with the constant name changes). 

I didn't think it would affect the actual race data, because hey, that was still just 22 drivers. 

Dutch GP race data itself: Bar chart showing how often cars were scrutinized compared to the expected number at the Dutch Grand Prix.  The values are displayed as a standardised residual.  Car 63 (Russell) was the most over-scrutinized compared to expected, with a value of 0.70, followed by cars 27 (Hulkenberg) and 41 (Lindblad) with a value of 0.35.  Cars 18 (Stroll), 31 (Ocon), 77 (Bottas) and 87 (Bearman) are the most under-scrutinized compared to expected with a value of -0.35.  8 cars were tested exactly as much as expected. Russell was the most scrutinized compared to expected, followed by Hulkenberg and Lindblad, with Stroll, Ocon, Bottas and Bearman the least scrutinized. 

What I don't understand is why Verstappen isn't on the under-scrutinized list given he was out before the end of the first lap, before Bearman who is on that list. 

Most peculiar. 

Any differences weren't statistically significant, with a χ² of 1.38. 

The thing I thought the Hadjar swap out-Tsunoda swap in would affect was the season-to-date ranking. But what I forgot was that, because it's observed vs expected, Tsunoda will still get a value for the one (or more depending on Hadjar's wrist) grand prix he participated in. 

The thing it changes is the χ² critical value, because Tsunoda's appearance increases the degrees of freedom in the data from 21 to 22. The critical χ² value goes up from 32.671 to 33.924. 

The season to date chart looks like this: Bar chart showing how often cars were scrutinized compared to the expected number for the season to date up to the Dutch Grand Prix.  The values are displayed as a standardised residual.  Cars 1 (Norris) and 63 (Russell) are the most over-scrutinized compared to expected, with a value of 0.61, followed by cars 5 (Bortoleto) and 44 (Hamilton) with a value of 0.50, followed by cars 3 (Verstappen) and 30 (Lawson) with a value of 0.35.  Car 18 is the most under-scrutinized compared to expected with a value of -0.81, followed by car 77 (Bottas) on -0.76 and car 11 (Perez) on -0.61.  2 cars were tested exactly as much as expected, 22 (Tsunoda) and 81 (Piastri). 

At the top, Bortoleto still stands out as not being like the other cars up there. 

At the bottom, it's still the cars that don't finish a lot, with Stroll and the two Cadillacs down there. 

Tsunoda's car has been tested exactly as much as expected after 1 race, and so has Piastri's after 12 races. 

The χ² value continues to go up, it's now 4.03, still nowhere near significant but rising. I think the cars being tested less than expected are the stronger contributors because their standardised residuals have larger values. 

We also didn't have a random check of a top 10 finisher, so the evidence is really piling up that that is a truly random check that only occurs sometimes and the early-season pattern was just a quirk of the numbers.