Explaining how the NBA draft lottery works

The NBA Draft Lottery is one league’s attempt to keep bad teams competing. It’s a moderately successful deterrent for tanking that gives every non-playoff team a chance at the No. 1-overall pick. It’s also a mechanism that can take a last place team and shunt it all the way to No. 4 through sheer dumb luck.

Fourteen teams will participate in 2017’s drawing Tuesday night. The winner will have the right to select between elite prospects like Washington’s Markelle Fultz, UCLA’s Lonzo Ball, and Kentucky’s De’Aaron Fox at the top of June’s draft. The Nets have the best odds to land the coveted No. 1 spot, but a regrettable 2013 draft means they’ll be swapping their pick, no matter where it lands, with the Celtics.

The NBA and NHL are the only two major sports leagues that eschew a straight-up “worst goes first” approach to their drafts. Every team that missed the 2017 playoffs is eligible to participate in the lottery, assuming they haven’t traded away their first-round draft choice. Boston, via Brooklyn, has a 25-percent chance to add a a potential franchise player at No. 1. From there, the odds get lower and lower until you get to the Heat, who have only a 0.5-percent chance to immediately improve their roster with the draft’s top prospect.

Before Tuesday’s broadcast, 14 ping pong balls, all labeled with different numbers 1-14, will be placed in a machine and drawn, one-by-one, until four have been selected. Those four numbers will create one of a possible 1,001 combinations. One of those combinations will be thrown out; the other 1,000 are distributed among the league’s non-playoff teams.

The Nets, with the league’s worst record, possess 250 of those combinations — though their pick will eventually be swapped with the Celtics’ pick. The Suns, who finished with the second-worst win-loss ratio, will get 199. Those totals decrease as teams get better, finishing with Miami’s five shots out of 1,000.

Once the top pick has been determined, officials will repeat the process for the second- and third-overall selections. Here are each franchise’s odds to earn a top-three pick Tuesday evening.

The results are then sealed in envelopes and taken to ESPN’s broadcast stage, where team representatives await their fates. Commissioner Adam Silver will unveil 2017’s draft order, starting with the No. 14 pick, to ratchet up the drama as executives, players, and fans alike wait to see where they’ll be making this year’s first-round picks.

Giving every non-playoff team a chance to land the top-overall pick may seem unfair to the truly horrid franchises in desperate need of a superstar infusion, but the NBA does it for a reason. The league used a traditional bottom-to-top draft order up until 1985, when accusations of tanking — purposely losing games in order to jockey for a top draft spot -- marred the Rockets’ acquisition of 1984 No. 1 overall pick Hakeem Olajuwon. In order to keep regular-season games competitive and avoid turning off fans, the NBA made sure having a rock-bottom record would no longer ensure a franchise-changing draft pick.

The system took a while to perfect. At first, each and every non-playoff team had equal odds to earn the top pick, and names were just drawn out of a hopper until the draft order was set. This led to controversy in 1985, when the Knicks, fresh off a 24-win season, jumped to the top of the queue and were awarded the chance to select Patrick Ewing with the first-overall pick.

In 1987, the system was changed so that only the first three picks would be determined by random draw. In 1990, then-Commissioner David Stern adopted the weighed lottery system that has slowly evolved into the drawing the league will use Tuesday night.

The lottery has been the subject of several conspiracy theories since its inception, thanks in part to its secretive nature. The non-televised nature of the drawing has led to criticism and accusations of rigging throughout the past two decades.

The league maintains it acts only in fairness, and has put several safeguards in place to prevent backstage shenanigans.

An independent representative from the accounting firm Ernst & Young will oversee the lottery drawing. Behind him or her, a handful of NBA officials, reporters, a machine operator, a timekeeper, and representatives from each of the 14 lottery teams present will work to ensure the process is truly random. Add in the league’s insistence no electronic devices can be used at the event until after the No. 1 pick has been awarded, and it’s tough to see how the process could be tampered with.