Shot differential (Corsi or Fenwick) has been shown to correlate strongly to puck possession and zone time, and to be a good predictor of future goal differential and wins. Previously, we showed how adjustments for score effects can improve the predictions appreciably and gave the Score-Adjusted Fenwick (SAF) standings.

It's been a month. After the jump, we'll update those standings and look at what's changed.

Here's the big table of raw data; at the bottom are some observations.

The fastest riser was the Rangers, who had a SAF of 47.8% through 46 games and are now at 49.1% through 58 games, suggesting their SAF over the last month was about 54.1%. Other risers include Anaheim (+1.1%), Minnesota (+0.9%), and San Jose (+0.9%).

The biggest drop was from the Blue Jackets, who had a SAF of 49.2% through 47 games and are now at 47.6% through 60 games, suggesting their SAF over the last month was about 41.8%. Other fallers include Edmonton (-1.1%), St. Louis (-1.0%), and Detroit (-0.9%).

Teams which SAF views more favorably than Fenwick Tied does include Vancouver (52.7% vs 50.2%), Philadelphia (51.6% vs 49.8%), Montreal (49.0% vs 47.3%), and Colorado (49.9% vs 48.4%).

Teams which SAF views less favorably than Fenwick Tied does include Washington (48.0% vs 50.9%), Florida (48.6% vs 51.2%), St. Louis (55.2% vs 57.3%), and New Jersey (50.2% vs 51.7%).

When this methodology was published, we took an extensive look at various metrics to show that the larger sample size of SAF gives a more repeatable measure of talent (higher split-half reliability) and gives better predictions (better correlations to future points%), especially over the first half of the year. However, some dismissed our score adjustments based on the observation that the two metrics end up similar by the end of the year. So let's look at whether -- and how -- that harmonizing is occurring this year.

The two metrics do appear to be getting closer together. League-wide, the coefficient of determination (r^2) between SAF and Fenwick Tied increased from 0.80 to 0.83 over the last month. Of the ten teams that had a gap of at least 1% between the metrics a month ago, none got appreciably bigger (max increase was 0.3%), but five got quite a bit smaller (decrease between 0.7% and 1.3%). The two metrics seem to be converging over time.

Next, let's look at how the metrics are converging. For the five teams whose gap between SAF and Fenwick Tied narrowed considerably in the last month, we can check whether the two metrics are moving towards each other to meet in the middle or if one of them is changing to catch up to the other.

• For one team -- Nashville -- the two metrics moved towards each other. Nashville's Fenwick Tied went up by 0.5% and their SAF went down by 0.3% as the metrics met in the middle.
• For four teams -- Philadelphia, Washington, Columbus, and Calgary -- their Fenwick Tied moved sharply towards their SAF.
• No team saw their SAF move sharply towards their Fenwick Tied.

Thus, there were four teams for which SAF told us a month ago what Fenwick Tied is just starting to suggest now, and there are no teams for which Fenwick Tied was ahead of SAF.

This is precisely what we would expect the benefit of the larger sample to be: SAF gives a more accurate talent evaluation earlier in the year. This is true across the board, and not just for these five teams -- as would be expected from the greater split-half reliability of SAF, the average change in Fenwick Tied was nearly twice as large as for SAF (0.9% vs 0.5%).

At this point in the year, Score-Adjusted Fenwick has largely stabilized at levels reflective of team talent, while SAF Fenwick Tied is still catching up. By the end of the season, the two metrics may give similar numbers, but for in-season predictions, the greater sample size is important. Moreover, given the enhanced importance of post-deadline performance, even end-of-year playoff predictions may benefit from having the kind of sample size that permits one to make good predictions while focusing on ~20-30 games of data.