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, Sagaba Konate of West Virginia posted a 15.64 block percentage in the 2017-2018 season. A block percentage of 15.64 percent was good for 2nd in the country.
Konater had 116 blocks playing in 61.6% of West Virginia's minutes. West Virginia opponent's attempted 1962 2-point field goals.
%Blocks = 100 * 116 / (.616 * 1962) = 15.64
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, Rhode Island's Stanford Robinson recorded a 4.36 steal percentage. This was 10th amongst all players in the 2017-2018 season.
Robinson posted 69 steals playing in 66.8 percent of his team's minutes. Rhode Island had about 2370 team possessions.
%Stls = 100 * 69 / (.668 * 2370) = 4.36