Adjusted scoring margin (ASM) calculations measure teams based on whether they score more or fewer points than their opponents on average give up, and vice versa. It's a somewhat similar theory to predictive power ratings but implemented in a different way. Every team has both an offensive and defensive ASM, and the sum of these two numbers is a team's overall ASM.
For example, imagine that at this point in the season, each of Team A's opponents has allowed an average of 70 points per game. However, Team A has scored an average of 75 points per game against that set of opponents. Team A's offensive ASM is therefore +5, which is a good thing. On average, Team A has scored five points more than its opponents typically give up.
Likewise, if Team A's opponents, on average, score 80 points a game, but manage to score 90 points a game against Team A, then Team A's defensive ASM is -10; that's not so good. (For consistency, we express good ASM's as positive numbers, and bad ones as negative numbers.) Team A's overall ASM is therefore an unimpressive -5, the sum of +5 and -10.
When two teams play each other, we can compare their respective ASM's to project the game's expected winner, win margin and final score, although you can get to those numbers a few different ways. ASM's accuracy tends to improve as more games are played.
Strengths: Looking at statistics in isolation often can be misleading, but adjusted scoring margins are relative measures. Giving up an average of 90 points a game may look bad compared to a league average, but not if you find out that the specific opponents a team has played actually average 105 points per game.
Weaknesses: The ASM method typically does not apply well when comparing teams with large differences in schedule or conference strength. Holding an ACC team to two points above its season average is probably a better performance than holding a Colonial League team to 2 points below its season average.