The NBA draft lottery will take place Tuesday May 19th, 2015. It is an annual event in which the NBA teams who had missed the playoffs in the previous season, or teams who hold the draft rights of another team that missed the playoffs in the previous season, participate in a lottery process to determine the order of the first fourteen draft picks. The lottery winner gets the first selection in the draft.
Under the current rules, 14 teams have lottery picks (with the number of lottery chances per each of the 14 teams being weighted according to record/finish (i.e. the worst team gets the most chances — in the form of additional ping pong balls randomly drawn one at a time). The lottery is weighted so that the team with the worst record, or the team that holds the draft rights of the team with the worst record, has the best chance to obtain a higher draft pick. The lottery process determines the first 14 picks of the draft.