On Saturday, I asked the question: Is TD/INT Ratio Now Meaningless? That question was shorthand for a less hot-takey view, but fortunately I’m lucky enough to have smart readers who engaged in some excellent discussion in the comments. One of those guys, Bryan Frye, brought up the idea of a TD/INT+ Ratio, or an era-adjusted version.

I spent a bit of time playing with different ways to adjust for era, including using Z-Scores. One problem there was that the variance in TD and INT Rates is pretty significant from year to year, which makes the Z-Score heavily influenced more by year-to-year fluctuation that true era adjustments. So here’s what I did, using Milt Plum in 1960 and Tom Brady in 2010 as examples. Those two players rank 4th and 5th in this system despite playing 50 years apart. The raw numbers? Brady had a 9:1 TD/INT Ratio with 36 TDs and 4 INTs, while Plus was at 4.2:1, courtesy of 21 TDs and 5 INTs.

1) First, we convert to rates. Plum threw 250 passes, while Brady had almost exactly double, with 492 attempts. Plum averaged 8.40 TD/100Att, while Brady was at 7.32 TD/100Att. On the other hand, Plum was at 2.00 INT/100Att, vs. 0.81 INT/100Att for Brady.

2) Next, we adjust for era, using only players who had enough pass attempts to qualify for the league passing crown, and taking a simple average of the rates of those players. Therefore, for the 1960 NFL season, the TD/100Att average was 5.34, while the INT/100Att average was 7.13. So Plum was at 157% of league average at throwing touchdowns and 357% of league average at avoiding interceptions.

Brady? Well, in 2010, the qualifying passers averaged 4.47 touchdowns and 2.78 interceptions per 100 pass attempts. This means he was at 164% of league average in touchdowns and 342% at avoiding interceptions

3) Finally, we multiply the two rates. So Plum’s Adjusted TD Rate times his Adjusted INT Rate was 5.61, while Brady was at 5.60.

Here are the top 300 seasons by this measure. The best season came from yes, Damon Huard in 2006. Here’s how to read the table below. Playing with the Chiefs, Huard threw 11 TDs and just 1 INT in 2006, an 11.00 TD/INT Ratio (the 3rd best ever). He threw 244 attempts that year, and averaged 4.51 TDs per 100 pass attempts. The league average was 3.89, so Huard was at 116% of league average. He threw just 0.41 interceptions per 100 attempts, while the league average was 3.05. That gives him an INT+ of 745%. Multiply those two numbers — 116% and 745% — and you get a value of 8.63, which ranks as the best era-adjusted TD/INT rate of all time.

As always, please leave your thoughts in the comments.