This article is part of our The Z Files series.
Last time out, I reviewed several things I'm thinking about as I set to embark on 2021 MLB projections. One of those things really has the wheels spinning, so let's dig a little deeper. Specifically, should 2020 numbers be adjusted for quality of competition?
In a normal 162-game season, teams play 76 games (47 percent) against divisional opponents, so the stats are somewhat influenced by the strength of their divisional foes, but there's ample play against other teams to dilute the bias and not have to worry about it. However, in 2020, 40 games (67 percent) were played within the division with the other 20 (33 percent) contested in the cross-league geographical zone. Each club faced only nine others. In a standard campaign, everyone plays 20 other squads.
Intuitively, quality of opposition must have played a part in the past season's performances. It may be that the quality is the same across the three regions, so it washes out. What if it is not, though? A batter's 110 wRC+ may not equate to the same level of hitter from one of the other divisional pairings. Pitchers with a 24 percent strikeout rate may not exhibit the same level of dominance if they pitched on a team in one of the other groupings.
Even if there is a difference, adjustments will be more empirical than data driven. Let's dig into some numbers to see what we're dealing with and perhaps add a little objectivity to a mostly subjective dilemma.