The idea of defense handedness is now well established I think – we recognize that ‘off hand’ defensemen often pay a penalty in terms of effectiveness.

Since some wingers also play on their off hand (a right shot left wing, or a left shot right wing), a few weeks ago I was mulling the idea of winger handedness.

Conventional wisdom suggests that doing this allows for:

• Greater effectiveness in the offensive zone (with the shot having a better angle to the net), but
• Less effectiveness in the defensive zone, where stick-off-boards makes for tougher defending and zone exits.

Dallas Eakins even experimented with putting Nail Yakupov (left shot right wing) on the left wing to try to manage his defensive woes (though this just seemed to confuse the young lad more).

I began to wonder if anyone has looked more broadly to see whether off-hand wingers are demonstrably more or less effective than on-hand wingers.  I put the idea out on Twitter, asking if anyone knew of work that had been done in the area.

It sparked an interesting and widespread debate, but it appears that it’s a relatively understudied issue.  This work by Arik Parnass (just hired by COL) vis a vis the power play was interesting.

@behindthenet’s brief look at overall handedness found some interesting anomalies.

But other than that, I found little or nothing specific to wingers.

So … why not do some initial digging into the idea?  Start by comparing wingers on their on hands vs wingers on their off hands, and see if there is a meaningful result as far as differences in points or shots or offense/defense.

Data

To pull this data, I used as my starting point the NHL ‘statsapi’ JSON live feed data.

This is an unusual source of data in that most fanalysts scrape the NHL roster sheets for player data. However, I have found the NHL roster sheets problematic for identifying positions (for example, Jordan Eberle has been listed as a C since he entered the league), while the JSON data entirely by visual scan appears to be more accurate.  Plus it very conveniently embeds the required data on player handedness.

So I used that.

The rest of the data for the players (boxcars and shot metrics) are scraped from the more conventional NHL game sheet data sources. All data used is for the 2015-2016 season. Any errors therein are my own, unless in the NHL data.

Process

As a starting point, I decided I would look at just a handful of key data points for comparison:

• points per game at even strength (EVP/Gm)
• goals per game at even strength (EVG/Gm)
• even strength shot attempts, percentage (CF%) as well as for and against rates per 60 (CF/60, CA/60) so as to be able to separate defensive and offensive effectiveness
• My own “Dangerous Fenwick” statistic, a distance and shot type weighted danger metric.  Again, percentage and for and against rates.

I did not filter the wingers for TOI or games played – if a player appeared on any game roster in 2015-2016 listed as right or left wing, that player was included in my data set. Measuring the effectiveness of a group like this suggests that we should include the ones who were ‘cup of coffee’ or bottom of roster types.

The wingers were separated into four groups: Left Wing/Left Shot, Left Wing/Right Shot, Right Wing/Right Shot, and Right Wing/Left Shot.  I then pulled demographic data, specifically country of origin and primary team in 2015, for each group.

Country of origin became of interest when I noted that the two off-hand wingers on the Oilers (Nail Yakupov and Anton Slepyshev*) are both Russian. In the same way that there is a distinct American bias in right handed defensemen, I wondered if there is a geographic bias in the development of off hand wingers.

*”Slappy” is listed as LW by the NHL, but by recollection the Oilers used him as a right winger at times. Not sure which is correct. This is another reminder that no dataset is ever 100% accurate.  We rely on data volume to account for such natural variability.

Raw Counts

On hand wingers are clearly the most common situation. Left wingers outnumber right wingers, just as LHD outnumber RHD.

The most common role for off hand wingers is a left shot right wing.

Team by Team

Counts for the categories of wingers by team are as follows (maximums are highlighted):

Though the numbers vary across the league, few teams look overly unusual in usage.  St. Louis (unusually high off hand RW) and Carolina (just one natural RW) both stand out to me.

Country of Origin

The following chart shows country of origin for each of the four categories of wingers:

Any country that did not have at least 10% representation in any one category was lumped together into Team Europe. If it’s good enough for the World Cup, it’s good enough for me!

Canada produces disproportionately fewer left shot right wingers, while Russia and Sweden produce disproportionately more off hand wingers.

There is a clear geographic bias to off handedness in wingers.

Effectiveness

The performance of the different categories of wingers is summarized in the following table.

* Technical note: The shot metrics are grouped i.e. the raw for and against counts are summed for each group, then divided by total (or summed EVTOI) to produce the percentage and the rates.

Notice something interesting: off hand wingers are producing slightly but distinctly better results than their on hand counterparts in every category. The off hand wingers score more points, more goals, and have better Corsi and Danger metrics.

This is the reverse of what is observed with defensemen, where being on the off hand typically carries a penalty.  With wingers, it appears to confer an advantage.

Furthermore, the improvement is not solely because of greater offensive impact (as you’d expect) – rather, both the for and against shot rates are slightly better.

This is not entirely expected.

Statistical Validity

Of course, the differences between each of these two groups, while distinct, may not be statistically valid given the inherent variance within the two groups.

To test this, I used a Welch’s t test (assuming independent samples with different variances) to compare each of the two groups of left and right wingers. I used CF% and points/game as the comparison statistics for test.

Note that the underlying data set for the purposes of this test treats each players seasonal results for CF% and points/game as one data point (different from the summary table above).

The results are somewhat counterintuitive:

The only statistic that was significant at 95% confidence was CF% for right wingers. Off hand right wingers produce a higher CF%, and the result is statistically highly significant.

The CF% difference for off vs on hand left wingers was significant at the 90% confidence level, but not the 95% level.

That RW is significant and LW is not despite being similar in magnitude is likely entirely due to the sample size, given there are only 19 off hand left wingers.

If I had applied a TOI filter, I suspect this would likely reduce the variance observed in the data and may have effected significance as well.  (Next time)

The difference in points/game between on and off hand for both left and right wingers was not statistically significant.

Conclusion

• At least one of the statistics show that there is a statistically significant difference between on hand and off hand wingers
• In general, off hand wingers had overall numbers that showed them to be more effective than on hand wingers, even from a shot suppression point of view. This is surprising.
• There is a distinct geographic bias in off hand winger country of origin, with Russia and Sweden being unusually common sources, while Canada is distinctly less proportionately likely to produce left shot right wingers.
• It remains unclear, but it’s possible that a part of the reason for the better off-hand numbers may boil down to a handful of superstar players. Ovechkin is one. And one of the highest scoring lines in the league features two off-handers (Patrick Kane and geriatric Calder winner Panarin), which is itself a point of interest.

This is a 40,000 ft view of the topic, but after this initial look, I would conclude that a deeper study on the topic is definitely warranted.

Particularly in identifying whether the apparent effectiveness of off hand wingers is a broad effect, or a narrow one confined to a handful of top players. Or is it selection bias, where only the best off hand wingers get played on the ‘wrong’ side in the first place?  And if it is a broad effect, why does the difference manifest in both offensive and defensive zone shot metrics, and not just on the offensive side?

And from there, understanding ultimately whether the effect has any tactical or roster implications for NHL teams.

Addendum – List of Off Hand Wingers