The NBA has designated the Rockets as the home team for their game tonight against the Thunder inside the Orlando bubble. At first glance, this designation seems largely irrelevant since home-court advantage does not exist inside the bubble — if anything the “road” team has an advantage.
The Rockets’ home status, however, does clarify a lingering doubt about the NBA’s procedure for determining home-court advantage in the playoffs. Specifically, the Rockets and Thunder ended the season with identical 44-28 records, but the Thunder won the head-to-head series 2-1. So why aren’t they the “home” team?
3-way ties and seeding
This is where the Jazz come into play. Utah also finished with a 44-28 record, creating a 3-way tie between the teams. The first criteria for breaking a 3-way tie is division championship — since the Rockets won the southwest division they were granted the highest seed. That set them as the No. 4 seed and then the Thunder were awarded the No. 5 seed by virtue of beating the Jazz in the head-to-head regular season series.
Here’s where the clarification comes in to play: The procedure to break the seeding tie puts the Rockets at No. 4 and the Thunder at No. 5. In prior seasons, once the playoff seeding had been set the NBA would then determine home-court advantage independently from the seeding.
Infamously, this created the scenario in which the Grizzlies had home-court advantage in the 2015 playoffs against the Blazers despite being the lower seed because Memphis had the better regular season record. At the time, division champions were guaranteed a top-4 seed, creating scenarios where a team might have a higher seed but a worse record than its opponent. When this happened, the team with the better record was granted home-court advantage regardless of seeding.
In other words, figure out the seeds to set the matchups first and then independently determine home-court advantage for each series.
After the Blazers/Grizzlies series, the NBA de-emphasized the importance of winning a division by no longer guaranteeing the division champ a top-4 seed, eliminating the silly scenario where a team could have a higher seed despite a worse record. They did, however, continue to use division championship as the top tiebreaker when three or more teams have the same record.
Under the multi-team tiebreaker rules, it’s still possible that a team could be granted a higher seed despite losing a head-to-head regular season series against their playoff opponent with an identical record. It almost happened last season, as well.
This scenario created an ambiguity in the rules. Would home-court advantage still be re-determined independently from seeding? In other words, after seeding teams in a 3-way tie, if two of those teams ended up matched up with each other would home-court advantage then be determined by applying the 2-team criteria (e.g. head-to-head record instead of division championship)?
Based on the NBA’s original language released in 2015, it did appear that home-court advantage and seeding would be determined separately.
Here is the language on the NBA’s official standings page as of November 2016 (archive.org link):
And some language from the 2015 press release announcing the current tiebreaking procedure (emphasis mine, available here):
The Board also approved changes to tiebreak criteria for playoff seeding and home-court advantage. Head-to-head results have become the first criterion to break ties for playoff seeding and home-court advantage between two teams with identical regular-season records; the second criterion is whether a team won its division. Under the old tiebreak system, a division winner was awarded the higher seed and received home-court advantage in a series if the two teams met in the playoffs.
This is slightly more ambiguous than the first link, but still explicitly mentions home-court advantage.
In contrast, as of today the NBA’s website uses identical tiebreaker language but does NOT mention home-court advantage at all:
Not a great rule
The NBA appears to have definitively clarified their rules by using seeding as a determiner of home-court advantage in the Rockets/Thunder series. On the one hand, it makes sense to simplify tiebreakers now that lower seeds cannot have better records than higher seeds, but it also creates scenarios where a team can lose a head-to-head series against a team with an identical record and still have home-court advantage. Is it fair that Oklahoma City will start on the “road” against Houston even though both teams have the same record and the Thunder won the regular season series? It won’t matter for the Thunder and Rockets in Orlando this year, but it may swing a playoff series in the future.