Player Efficiency Rating was introduced in 2007 by John Hollinger, as a means of measuring a player's overall greatness and production. 15 is indicative of an average player, 20 is indicative of an All-Star player, and 25 is symbolic of an MVP and superstar-level player.
The higher the score, the better the player.
With that being said, let's take a look at the best players in Boston Celtics history, based on PER.
Ranking the best Celtics players based on PER
7. Paul Pierce- 20.6
Paul Pierce was nicknamed "The Truth" for a reason: he was a menace and could always get a bucket. Pierce spent 15 years in Boston, making 10 All-Star teams, four All-NBA teams, and a championship in 2007-08.
6. Kevin Garnett- 21.1
Kevin Garnett is one of the game's greatest players in league history and is especially one of the best big men, despite playing in an era that was littered with stellar bigs. KG joined the Celtics after realizing he had no chance of winning a title with the Minnesota Timberwolves.
KG won one championship with the Cs and game eerily close to winning another.
5. Ed Macauley- 21.7
Ed Macauley was selected by the Celtics in the 1950 dispersal draft and remained in Boston for six seasons. Macauley made the All-Star team in all six seasons, averaging 18.9 points and 8.1 rebounds, while also making four consecutive All-NBA teams.
4. Robert Williams III- 22.3
Robert Williams being this high on the list may raise doubts about the metric. Big men tend to score higher in PER than guards, because they impact the game in a number of ways, such as blocking shots, nabbing rebounds, and scoring efficiently.
Williams played five total seasons in Boston and emerged as one of the league's best young big men in 2021-22, averaging 10 points, 9.6 rebounds, 2.2 blocks, and 73.6 percent from the field, while also making Second Team All-Defense.
3. Larry Bird- 23.5
Regardless of which era you started watching basketball, you've heard of Larry Bird. Regardless of how old you are, you know of his greatness.
Bird is one of the league's best 15 players of all time, without question (some have him higher), and he's largely responsible for the NBA's resurgence, along with Michael Jordan, Magic Johnson, and others.
2. Isaiah Thomas-23.8
Isaiah Thomas bounced around the league a bit before landing in Boston in 2014. Thomas became a fan favorite because of his ability to maximize his diminutive, 5-foot-9 185-pound frame.
Thomas was the game's best fourth quarter scorer in 2016-17 and became an MVP finalist, averaging 28.9 points, 5.9 assists, 46.3 percent from the field, and 37.9 percent from three. In the postseason, Thomas put the team on his back and played through the devastating tragedy of losing his sister.
In spite of this, the Celtics traded him to the Cleveland Cavaliers, in exchange for Kyrie Irving, showing sports fans globally just how cold the game can be.
1. Kyrie Irving-24.6
Kyrie Irving is easily one of the most skilled players in the history of the league. He has a smooth feel for the game and an insane handle, which is essentially impossible to stop.
And he's a reliable outside shooter (39.3 percent for his career). Kyrie helped lift LeBron James and the Cleveland Cavaliers to a championship and forced a trade out of Cleveland, landing in Bean Town in 2016, where he remained for two seasons, averaging 24.1 points, 6.1 assists, 4.4 rebounds, 48.9 percent from the field, and 40.4 percent from three, before leaving the franchise in free agency, to join forces with Kevin Durant (and later James Harden) with the Brooklyn Nets.