o determine whether there were differences in the tenures of white and black coaches in the National Basketball Association, The New York Times examined all coaching tenures in the N.B.A. since 1989. Other factors that could be related to a decision to dismiss a coach were also examined.

The calculations were based on 159 coaching tenures, involving 110 different coaches, who either left their positions voluntarily or were dismissed. Only completed tenures were used in the calculations. Those currently coaching were not included, because some were hired very recently and that could skew the results. Any tenure that lasted fewer than 10 games was also excluded.

Team performance turned out to be the most important factor in a coach's job security; winning games and making the playoffs strongly correlated with longer coach tenures. The quality of the team before the coach took it over was also a factor. But white coaches tended to keep their jobs longer than black coaches even when those factors were taken into account.