1/a in the EGD rating system

1/a predicted EGD | 1/a observed EGD | 1/a predicted revised | 1/a observed revised

p predicted EGD | p observed EGD | p predicted revised | p observed revised

rating point contibutions EGD | rating point contributions Revised

rating points for game results EGD | rating points for game results Revised |

The horizontal axis shows the go rating scale used by the EGD and the revised rating system.
The vertical axis shows units of log-odds per rating point.

The thick blue line is 1/a in a standard Elo rating system: 1/a = ρ(r) => ln(10) / 400
The red line is 1/a used by the EGD rating system: 1/a = ρ(r) => r < 2700 ? 20 / (4100 - r) : 1 / 70
The black line is a fit to 1/a observed in the EGD history: 1/a = ρ(r) => 0.0022 + 0.000025 * exp(rating / 440)