To put it simply, DVOA (a metric created by Football Outsiders) tells us a little bit more about a team’s strengths and weaknesses than “yards per” can account for. If a team ranked 8th in yards allowed per carry, for example, but were 16th in DVOA, it would essentially mean that they weren’t as good as that first statistic made them appear.
DVOA accounts for matchup, as well as for things like teams running out the clock, or third-and-one/goal-to-go, or one super long run that wrecked a team’s yards allowed per carry.
DVOA is basically like saying, “If everyone played neutral matchups all year and nothing fluky happened, this is roughly how the teams would end up being ranked.”
It’s not incredibly useful as a predictive tool, but it is a strong baseline for understanding a matchup at a glance.