The articles main three arguments are
Bradley is ranked 44th among all NBA point guards in ESPN’s defensive real plus-minus (DRPM).
Avery’s straight on/off numbers are really bad, actually — at least on the defensive side of the ball.
Synergy data, which measures how a player performs when the person they’re guarding turns the ball over, shoots, or gets fouled. Again, Bradley is ranked in the 44th percentile, which just deemed “average” by Synergy.
Ok his first argument
Bradley is ranked 44th among all NBA point guards in ESPN’s defensive real plus-minus (DRPM).
then he proceeds to destroy his own argument by saying
Then again, real plus-minus isn’t the perfect stat to measure a player’s defensive impact.
I went to the espn defensive real plus and minus. This year they said rondo was a better defender then jrue holiday and mike conely. You know rondo who says he stopped playing defense. the kings defense was so bad they had a major starting line up change to make it stronger. Making 19 min a game seth curry a starter. (seth has done well btw) Oh and according to that site goran dragic is the number 10 best defender for a pg. That seems legit.
2nd argument
Avery’s straight on/off numbers are really bad, actually — at least on the defensive side of the ball.
that is more of a team stat and hard to pin point if thats him or the players he normally plays with. for example amir johnson has been starting but only playing like 20 min. Making a weak defensive front court so that could be a factor. Also our bench is amazing. Which is on when badly is off. even turner and jerebko are good defenders. smart is an amazing defender. Also bench tends to score less then starting line ups. Just some factors that may effect the stat.
3rd argument
Synergy data, which measures how a player performs when the person they’re guarding turns the ball over, shoots, or gets fouled. Again, Bradley is ranked in the 44th percentile, which just deemed “average” by Synergy.
Um I am unfamilar with synergy and was unable to find where or how they make their data. It could be accurate. However to quote the author "There isn’t a PER for defense yet, so we have to look at other data before we get to the whole “eye test” scenario basketball fans have been trotting out ever since John Hollinger first cracked open a Bill James book." Meaning one stat cannot define their effectiveness.
Avery has received high praise from other players around the league. There is no real data to show how someone defends the perimeter
But we do have this amazing highlight as evidence
https://www.youtube.com/watch?v=wpA2LX0JXTwThen their is this article
http://espn.go.com/blog/boston/celtics/post/_/id/4722655/peers-stumping-for-avery-bradley-in-firstteamalldefense-campaign