The table below measures a player’s career impact on the offensive end. Impact is a comparison of the player’s per-possession production rate with the league average per-possession values for the league in the given season. In all columns, the impact is calculated as Actual – Expected. This means that for some columns (like TOV and MISSES), it’s better to have a negative score. A negative score means that the player turns the ball over less frequently than average in her context. There are some columns, however, where it is better to have a positive value (PTS, FGM, etc)
Further explanation of these differentials is here. You can view the same values in color-mapped bar charts in the Career Dashboard.