From AoA sensors and displays is on PFD. Error as much as 3%. (not 3 kts!).
I stand corrected. Haven't read the FCOM bulletin for a while.
However I do think that in daily life the accuracy is much higher than that. The error should work in both ways, and I have very rarely seen a discrepancy which would lead to believe that we are lighter than we actually are. But I guess it's not down to me to comment on published accuracies.