APBRmetrics

Has anyone noticed that HCA is more significant as the playoffs progress? I checked data on the CF and finals and found HCA to be significantly higher than the usual regular season HCA (60%, ~3.5 ppg).

Conference finals since 1985:

Overall home teams:
212-109 (.660) record
+4.32 differential
37-19 (.661) series record for team with HCA

So teams with HCA win on average 2/3 of their home games in CF.

team with HCA in series, in home games:
122-50 (.709) record
+5.27 differential

team w/o HCA in series, in home games:
90-59 (.604) record
+3.22 differential

Game 6, home team (team w/o HCA in series):
23-14 (.622) record
+3.30 differential

Game 7, home team:
11-2 (.846) record
+8.46 differential

Team with HCA for series in CF:
5-5 series record when having a worse SRS
7-4 series record when SRS difference is between 0 and +1

Team w/HCO in series at home:
+1.98 better than opponent in regular season (by SRS)
+5.27 point differential
+3.28 HCA (5.27-1.98)

Team w/o HCO in series at home:
-1.97 worse than opponent in regular season
3.22 point differential
+5.19 HCA

Average HCA is +4.24 based on that.

Teams that are within -1 to 1 SRS of each other:
Home team: 69-35 (.663)
home team: +3.85 point differential

Teams that are within -0.5 to 0.5 SRS of each other:
Home team: 46-23 (.667)
Home team: +4.10 point differential

Games 6 and 7 for teams within -1 to 1 SRS of each other:
home team: 12-4 (.750) record
point differential: +5.19


Finals since 1985 (2-3-2 format instituted):

Overall home team:
96-61 record (.611 win%)
+4.62 point differential
20-8 series record

Team with HCA in series in home games:
54-23 (.701) record
+6.57 differential

Team w/o HCA in series in home games:
42-38 (.525) record
+2.74 differential

Games 6 and 7, Home team:
15-6 (.714) record (all 4 game 7 winners were home teams)
+5.48 Differential

So HCA goes from 60% to about 2/3 later in the playoffs. That increase is staggering if you adjust for the fact that both teams have about equal travel (road teams dont in reg season) and the fact that rest is equal (road teams sometimes play back to back in reg season). If you adjusted for that, maybe the HCA is worth 5 PPG later in the playoffs.

Very interesting stuff. You have averages for 56 conference finals.

Team w/HCO in series at home:
+1.98 better than opponent in regular season (by SRS)
+5.27 point differential
+3.28 HCA (5.27-1.98)

Team w/o HCO in series at home:
-1.97 worse than opponent in regular season
3.22 point differential
+5.19 HCA

Average HCA is +4.24 based on that.

The team with series HCA, generally the better team (by season SRS) does not have a larger than normal HCA in games.
The larger than normal swing between home and away is entirely due to the underdog team's enhanced ability to win at home.

It may well be that a team which has reached the conference finals is apt to be playing better than their normal for the season -- but only at home?

team w/o HCA in series, in home games:
90-59 (.604) record
+3.22 differential

Game 6, home team (team w/o HCA in series):
23-14 (.622) record
+3.30 differential

Game 7, home team:
11-2 (.846) record
+8.46 differential

When 2 teams are so evenly matched that they've split the first 6 games, the visiting team wins game 7 just 15% of the time.
That's somewhat better than the odds of an 8 seed upsetting a 1 seed; or coming back from a 3-1 deficit.
OK, it's about half as likely as their winning an earlier road game; or it's a small sample. That point differential is impressive, though.

In the previous game, that underdog team had a 62% chance of winning at home vs the same team that had the better season record AND was up 3-2 in the series.

In the 1995 WCF, Hou-SA, the visiting team won the first 5 games, before Houston 'broke through' with a win at home.
Without that series, the HCA team is .722 at home in CF games.

2nd round data. 112 game series sample size (631 games)

Overall home teams:
90-22 (.804) series record for team w/HCA
424-207 (.672) home team record
+4.92 point differential in home games
+2.74 reg season SRS difference between team with HCO and w/HCO in series

Team w/HCA in series at home:
270-79 (.774) record in home games
+7.48 point differential
+2.76 better than opponent in reg season (by SRS)
+4.72 HCA

Team w/o HCA in series in home games:
154-128 (.546) record in home games
+1.76 point differential
-2.71 worse than opponent in reg season (by SRS)
+4.47 HCA

Game 6, home team (team w/o HCA):
33-25 (.569) record
+3.24 point differential
-2.33 worse than opponent based on reg season SRS
+5.58 HCA

Game 7, home team:
24-6 (.800) record
+7.1 point differential
+2.19 better than opponent in reg season
+4.91 HCA

So in the 2nd round, the advantage still exists.

Home teams overall since 1985 in 2nd round, CF, and finals:
732-277 (.660) record
147-49 (.750) series record for team with HCA
+4.70 point differential

Home team; Game 7, 2nd round, CF, and finals:
39-8 (.830) record
+7.30 point differential
+1.97 better than opponent in reg season by SRS
+5.32 HCA

So they win about 2/3 of the games and the advantage is worth about 4.50 points and HCA teams win 75% of series. It's obvious that HCA is pretty big in the playoffs.

Great information, only disagree on one thing.

HCA is big if you get to a game 7, otherwise it is not something teams should worry about. When the Bulls won 6 titles they played in 2 Game 7's out of 24 series.