Skip to main content
Some drivers seem to find an extra tenth at certain tracks year after year. This heatmap measures that: for each driver and circuit, how much faster or slower they tend to be there relative to their own season-average pace, after constructor and field effects are removed. Negative (green) means faster than the driver’s average at that circuit; positive (red) means slower.

​
What it shows

Each cell is one driver × circuit affinity:
  • Shrunk affinity: a Bayesian posterior mean that pulls the raw observed circuit delta toward the driver’s global mean, using 5 virtual races as the prior weight. Drivers with fewer observations are shrunk more aggressively toward neutral.
  • Sign convention: negative = faster than the driver’s own average at that circuit (green); positive = slower (red) the same convention as the driver skill residual.
  • Confidence: the fraction of the posterior coming from data versus prior, n_obs / (n_obs + 5). Values below 0.17 (one race) are prior-dominated.
Drivers are sorted fastest-to-slowest by median affinity across circuits; circuits are sorted alphabetically.
Cells are shown only when n_obs ≥ 2 (two or more races at the circuit). Single-race visits are excluded as unreliable, so empty cells mean too few visits, not zero affinity.

​
How to use it

  1. Select a season scope from the filter bar; the heatmap reloads.
  2. Scan a driver’s row for their strong (green) and weak (red) circuits.
  3. Scan a circuit’s column to see which drivers historically over-deliver there.
  4. Check confidence before concluding a strong colour on a low-confidence cell is mostly prior, not signal.

​
Reading the signal correctly

Affinity is within-driver: it compares a driver to themselves, so it is not a pace ranking. A slow-car driver can show strong positive affinity at a circuit that suits their style, independent of where they finished.
Affinity and the era ratings share an underlying skill residual; do not stack them as if independent. A circuit where a whole era’s data is thin (few events) will show wide, prior-dominated cells read the confidence column. See the decomposition limitations.

​
Data source

The chart queries int_driver_circuit_affinity via DuckDB-Wasm in the browser. The data window covers 2018–2024. For the full model definition, see the int_driver_circuit_affinity reference.