Accuracy of Betting Lines, by Week# (during five years 2017-2021)

Here's some perspective for you, if you feel a season is going unpredictably and want to know what’s normal.

Knowing the accuracy of betting lines especially relates to all positions in fantasy, but especially D/ST, because correctly guessing winners is key to good prediction. Betting lines give an objective look (affecting all rankings, not just mine).

This below chart highlights the mid-season of 2021.

I could generate a plot of "%Upsets per week", but here I stick with my usual look at correlation. A higher correlation means that Vegas was good at guessing game scores; a negative correlation means there were more upsets than correct picks.

r/fantasyfootball - Stream w/Consciousness -- Week 13 -- Top D/ST & K -- Overview of betting lines' week-to-week accuracy


  • Normal correlation is between 0.25 - 0.55

  • Yes week 1 is usually least predictable... but predictability quickly corrects by week 2

  • Betting line predictability does not really improve over the season (as many people think).

  • The 2021 season was

    • manic in weeks 2-6...

    • but weeks 7-11 were depressive

    • and weeks 8, 9, 10, and 11 were significantly below normal.