The NBA’s draft lottery, which takes place every spring between the end of the regular season and the draft, is the league’s way of determining the draft order and disincentivizing second-half tanking. The lottery gives each of the 14 non-playoff teams – or whichever clubs hold their first-round picks – a chance to land one of the top four picks in the draft.
Although the top four picks of each draft are up for grabs via the lottery, the remaining order is determined by record, worst to best. The league’s worst team isn’t guaranteed a top-four spot in the draft, but is tied for the best chance to land the first overall pick and will receive the fifth overall selection at worst.
The first four picks are determined by a draw of ping-pong balls numbered 1 through 14. Four balls are drawn, resulting in a total of 1,001 possible outcomes. 1,000 of those outcomes are assigned to the 14-non playoff teams — for instance, if balls numbered 4, 7, 8, and 13 were chosen, that combination would belong to one of the 14 lottery teams. The 1,001st combination remains unassigned, and a re-draw would occur if it were ever selected.
The team whose combination is drawn first receives the number one overall pick, and the process is repeated to determine picks two, three, and four. The 14 teams involved in the draft lottery are all assigned a specific number of combinations, as follows (worst to best):
- 140 combinations, 14.0% chance of receiving the first overall pick
- 140 combinations, 14.0%
- 140 combinations, 14.0%
- 125 combinations, 12.5%
- 105 combinations, 10.5%
- 90 combinations, 9.0%
- 75 combinations, 7.5%
- 60 combinations, 6.0%
- 45 combinations, 4.5%
- 30 combinations, 3.0%
- 20 combinations, 2.0%
- 15 combinations, 1.5%
- 10 combinations, 1.0%
- 5 combinations, 0.5%
If two lottery teams finish the season with identical records, each team receives an equal chance at a top-four pick by averaging the total amount of outcomes for their two positions. For instance, if two teams tie for the league’s fourth-worst record, each club would receive 115 combinations and an 11.5% chance at the first overall pick — an average of the 125 and 105 combinations that the fourth- and fifth-worst teams receive.
If the average amount of combinations for two positions isn’t a whole number, a coin flip determines which team receives the extra combination. For example, if two clubs tied for the league’s third-worst record, the team that wins the coin flip would receive 133 of 1,000 chances at the first overall pick, while the loser would receive 132. The coin flip also determines which team will draft higher in the event that neither club earns a top-four pick.
The table below displays the odds for each lottery team, rounded to one decimal place. Seeds are listed in the left column, while the picks are noted along the top row. For our purposes, the first seed is the NBA’s worst team.
It’s worth noting that the NBA’s lottery format was recently changed, with 2019’s draft representing the first one that will use the new system. Previously, only the top three spots were determined via the lottery, and the odds were weighted more in favor of the league’s worst teams.
For instance, in 2018, when the league-worst Suns landed the first overall pick, they had a 25.0% chance to receive that No. 1 selection heading into the lottery, and couldn’t have dropped further than No. 4 (35.8%). In 2019, the NBA’s worst team will only have a 14.0% chance at the top pick and will have a 47.9% chance of falling all the way to No. 5.
Note: This is a Hoops Rumors Glossary entry. Our glossary posts will explain specific rules relating to trades, free agency, or other aspects of the NBA’s Collective Bargaining Agreement. Information from Tankathon.com and Wikipedia was used in the creation of this post.
Earlier versions of this post were published in 2012 and 2013.