Basketball Reference's data is largely complete for most stats going back to the league's founding. However, there are enough missing records before the 1983-84 season that we don't feel comfortable definitively listing single game records prior to that season.
Notable exception: Points scored. This record is complete enough that we do list it for earlier seasons.
This cutoff does exclude many of the sport's legends from the single game record lists. We recognize that's a meaningful loss, but we've decided it's preferable to listing records that might later prove incorrect if and when new data is uncovered.
For a season-by-season breakdown of how many game records are missing, see our Data Coverage Summary.