Hardest circuits as seen in Teammate gaps
"The theory being that if two drivers have the same car, then on a less challenging circuit, their times will be close together as there is little opportunity for one to shine. But on a really tough track, the better driver will eke out a few more tenths.
So if we take this lens, this is what we see. The metric is qualifying gap as a % of average for the year. So if the average qualifying gap for 2012 was T%, then we would expect it to be 1.2T% at the Buddh Circuit.
Ergast ( Ergast Home Page ) database was used to pull all qualifying times from 1994 onwards
Qualifying gap was defined as the gap between teammates' times in the last qualifying round that they both participated in (thrown out if >20s, because I think some crashes were kept in the data as times)
The median gap (as a % of faster teammate's laptime) laptime was taken for each circuit and for each year.
Those were divided to give the overall result. Edit: this second normalization is necessary because absolute qualifying gap has come down a lot since the 90s. I'll publish this separately.
Clustering was applied to divide the tracks into 5 groups
Well, it is an interesting methodology, but is subject to a much greater degree of random variation if there are only one or two seasons of data used as opposed to 20+. So Jerez only has one season of data and Fuji only has two. A couple of drivers having a bad day can bias the results.