DavidStern wrote:So why not always look at playoffs SRS?
And BTW, if teams are not playing at their actual true level in regular season, then everyone should answer one question: why is it happening?
This is a great question and I sometimes wish we had better reference threads here for topics like this. In short, I see 2 factors that you need to really consider:
(1) Sample Size (variance/accuracy) When is a team at their "true" SRS? After 40 games? 60 games? 80 games is a good, strong sample, no doubt, but is that the EXACT number they would end up at if they played the season over and over? Not quite. As Sideshow said, when you add in the issue of health/consistency, while 82 games is a good sample it's not a perfect reflection of the actual quality of a team
after 82 games (which is an arbitrary number).
(2) Opponents/MatchupsHave you ever considered what a team outside of Miami's SRS would be if LeBron missed the season? Or if the Kings were contracted? If you play around with these numbers, you'll see that some teams match up slightly better with other teams. A tanking team can influence SRS in different ways,
depending on the matchup. So can an injured one.
If you remove the Celtics from the 60's (an extreme example because of the small league), suddenly the 62 76ers are a 5 SRS team and best in the league. Is that "really" what they were?
In total, SRS is a great tool because points are a great tool because basketball games end at psuedo-random times. However, the SRS you see at the end of the RS next to a team's name isn't a perfect indicator of its strength because of reasons like these. In the same way we can talk about portability for a player, we can talk about it for a team -- some 4 SRS teams matchup great with a bunch of elite teams (versatile and highly consistent strengths regardless of matchup)...I would not think of those teams as merely "4 SRS teams."
PS The Playoffs are a small sample -- I would never suggest using it alone. The interpretation you must make is in how much to view the PS (or a select end-of-season sample) as a "better" indicator of a team's strength. I personally do this in conjunction with health, lineup data, matchup analysis, etc.