two ways to achieve that, by gaining yards and getting first downs. These two goals need to be balanced to determine a player's value or a team's performance." There is a separate DVOA measurement for special teams, which "compare[s] each kick or punt to the league average for based on the point value of field position at the position of each kick, catch, and return." DYAR DYAR (Defense-adjusted Yards Above Replacement) calculates each player's cumulative value above or below a "replacement-level" alternative. DYAR differs from DVOA in calculating a player's total value through the course of a year, and not on a play-for-play rate. States Football Outsiders, "DVOA, by virtue of being a percentage or rate statistic, doesn’t take into account the cumulative value of having a player producing at a league-median level over the course of an above-average number of plays. By definition, a median level of performance is better than that provided by half of the league and the ability to maintain that level of performance while carrying a heavy work load is very valuable indeed." Adjusted Line Yards Adjusted Line Yards (ALY) "differentiate[s] between the contribution of the running back and the contribution of the offensive line." ALY attempts to "separate the effect that the running back has on a particular play from the effect of the offensive line (and other offensive blockers) and the effect of the defense. ... Yardage ends up falling into roughly the following combinations: Losses, 0-4 yards, 5-10 yards, and 11+ yards. In general, the offensive line is 20% more responsible for lost yardage than it is for yardage gained up to four yards, but 50% less responsible for yardage gained from 5-10 yards, and not responsible for yardage past that. Thus, the creation of Adjusted Line Yards." Drive Stats Drive Stats calculate a team's average success rate on a possession-by-possession basis: "[E]ach team's total number of drives as well as average yards per drive, points per drive, touchdowns per drive, punts per drive, and turnovers per drive, interceptions per drive, and fumbles lost per drive. LOS/Drive represents average starting field position (line of scrimmage) per drive from the offensive point of view. Drive stats are given for offense and defense, with NET representing simply offense minus defense." Pythagorean projection Another metric Football Outsiders uses is Pythagorean projection, which estimates wins in a season by a formula originally conceived by baseball analyst