[1] Speed score is on a scale of 0 to 10, with zero being the slowest and ten being the fastest.
[2] Speed Score is calculated using six factors: stolen base percentage, stolen base attempts as a percentage of opportunities, triples, double plays grounded into as a percentage of opportunities, runs scored as a percentage of times on base, and defensive position and range.
The average of factors 1 through 6 is taken, and the result is the player's score.
In 2006, Baseball Prospectus developed their own version of speed score in order to "better [take] advantage of play-by-play data and [ensure] that equal weight is given to the five components.
"[5] It is on the same zero to ten scale and includes all the original factors (except for the player's defense).