To test the effectiveness of turning off your meter we set our automated script to run 200 shot samples every 5 milliseconds for a 100 millisecond range for Base 3. For context the yellow bar on the shot meter is roughly 115 milliseconds long. We found the center of the green window for Base 3 then went 50 mS in both directions taking samples.
As you can see from the charts the boost for No Meter vs Meter is smaller in 2k21 than it was in 2k20. This seems to be consistent across all rating levels.
Reading the Chart
The graph shows the speed of the shot in milliseconds along the bottom axis and the make percentage on the left axis. The data points represent the make % out of 200 shot attempts for that specific speed.
The Blue line shows the no meter make percentage and the orange line shows the Metered Make percentage.
Meter vs No Meter
90 Rating 2k21
90 Rating 2k20
75 Rating 2k21
75 Rating 2k20
So Should I Turn Off My Meter?
Yes. The boost you get from turning your meter off is worthwhile.
However, it's important to point out that poor timing is heavily punished. There is a 30% drop in make rate if you miss the green window entirely, even if its just by 5mS. Don't turn it off until your timing is there.