A player's defensive ability can be measured using blocks and steals.
Block Percentage (%Blocks)
Steal Percentage (%Stls)
Block percentage is the percentage of opponents' 2-point shots that are blocked by an individual player while he's on the floor.
%Blocks = Total Player's Blocks / (%Min * Opponents' 2-point attempts)
For example, Chris Boucher of Oregon posted a 11.77 block percentage in the 2016-2017 season. A block percentage of 11.77 percent was good for 10th in the country.
Boucher had 79 blocks playing in 46.5% of Oregon's minutes. Oregon opponent's attempted 1438 2-point field goals.
%Blocks = 100 * 79 / (.465 * 1438) = 11.77
Anything over 8 percent is above average according to KenPom.
Steal percentage is the percentage of possessions that a player registers a steal while he's on the court.
%Stls = 100 * Steals / (%Min * Team Possessions)
For example, VCU's Doug Brooks recorded a 4.5 steal percentage. This was 9th amongst all players in the 2016-2017 season.
Brooks posted 56 steals playing in 50.3 percent of his team's minutes. VCU had about 2450 team possessions.
%Stls = 100 * 56 / (.503 * 2450) = 4.5