All goals are not the same...
Updated: Tuesday October 23, 2001 7:25 PM
By Marc Foster and Chris Apple, special to CNNSI.com
All men may be created equal, but not all goals are. In a previous column, we examined the effects of scoring and ice time vs. points per games to measure efficiency of goal scoring. Yet another way to measure efficiency is to look at the situation in which goals are scored. I don't think anyone would argue that the most important goal is often the first one and in this the age of goaltenders like Dominik Hasek and Patrick Roy, one goal can mean the difference between victory and defeat. To better see the effect of scoring, we can measure "weighted goals," where we take the goals scored and revalue them based on the difference that goal makes in the score of the game.
One point is assigned to any goal that results in a tie or leads to a one-goal lead. A goal that adds to a one goal lead or reduces a two-goal lead to one, is valued at 0.75 weighted points. For any goal that cuts a three-goal lead or adds to a two goal lead, 0.50 weighted points, and 0.25 points are assessed for adding to a 3-4 goal lead or reducing a 4-5 goal lead. Finally, just 0.10 weighted points are assigned for any goal that adds to more than a five-goal lead or reduces more than a six point lead. If a player scores into an empty net, this results in reducing the weighted value by one category. For example, if Mario Lemieux scores to give a two-goal lead to the Penguins, he would receive 0.75 weighted points, however if that same goal was an empty-netter it would only be worth 0.50.
While this re-valuing of goals does not radically shift the leaderboard for goals, if we want to measure the effectiveness of a goal scorer, we take the weighted goals and divide them by the total number of goals scored by that player. This creates a weighted goal-efficiency percentage that proves useful in measuring both the goal scorer and his role in winning and losing. For example, we can look at Detroit's Brendan Shanahan, who has an average overall weighted goal-efficiency at 87.5 percent with seven weighted points in eight goals. In even-handed situations, his weighted goal-efficiency sits at a remarkable 100 percent, his short-handed he ranks a strong 91.7 percent, only on the power play does his efficiency drop to a 62.5 percent. To contrast that, Mark Parrish of the N.Y. Islanders, who's overall weighted goal-efficiency is comparable to Shanahan's with 7.75 points in 8 goals or 86.1 percent, with a significantly lower even-strength percentage of 87.5 percent and on the power play, slightly lower at 83.3 percent.
While much of the reason for a higher or lower efficiency rating can be contributed to the difference in scoring in any given day, it can also be an effective measuring tool for how well a given player contributes to the winning of a team. Just because John LeClair might have a 91.7 efficiency percentage, does not mean that he will tie the score or give a one-goal lead 91.7 percent of them time. It does mean that he has a high level of contribution to the winning of his team. This could be either due to the fact that Buffalo has been playing close games and he has been scoring or that in a blowout he is contributing by scoring early in the game when the differential is lower. The higher the efficiency percentage, the higher level of contribution the player has given to winning.
If we look at the NHL leaderboard for goal-scorers, we can see what a wide range of weighted goal percentage the top seven scorers in the league have. We've already looked at Parrish and Shanahan, who both have strong average weighted percentages, but if we look at Washington's Peter Bondra, we can see what a difference his scoring makes on his percentage. In Bondra's seven goals scored, he has a combined 4.75 weighted goals, with only 1.5 (2 goals) of those goals scored in even-strength situations. The remaining 3.25 weighted goals (5 goals) were scored on the power play when the team was up by an average of 2.2 goals. However if we jump just one spot down on the list, we see that both LeClair and Yashin score strong in weighted goals with an 91.7 percent (5.5 wGF out of 6 goals) average for both of them. LeClair is stong even-handed with 4.5 weighted points out of 5 goals (90 percent) and 1 of 1 (100 percent) on the power play. While Yashin is slightly stronger at 3 out of 3 (100 percent) even-strength, all of his goals giving the Islanders a one-goal lead. He has also a significantly contributing to the power play of the Islanders with 2.5 out of 3 goals (83 percent). While tied in scoring, St. Louis's Demitra and Edmonton's Carter have lower overall percentages.
From these numbers we can see how although scoring goals is important in the NHL; the quality of those goals can also be measured. This gives us an effective tool to compare and contrast goal scorers and allows us to see how their scoring impacts a team's ability to win and lose. If we couple this new weighted goal-efficiency with the scoring efficiency that was discussed in the column, Good goals and bad goals, we see an effective way of measuring the scoring potential of a player and his contribution to the success of a team.
Another application for the weighted goal efficiency is to look at the overall average for a team. While the weighted goal percentage can mean different things depending on a couple of different factors, it does give us an interesting look into the teams and future potential. For example, if we look at the teams of Nashville (13.75 of 14) and Atlanta (13.5 of 14), we can see that although they both have losing records, the relatively high weighted goal percentages shows us that the quality of their combined goal scoring is high. So although they may be losing in the end, they are managing to keep the games they play in relatively close. This should give some warning to teams not to easily overlook these opponents as they could have the potential to generate an upset.
We can likewise see that teams such as Florida (9.5 of 14) and Pittsburgh (11.75 of 16) may suffer from defensive woes or goaltending situations and find that they often find themselves in scoring deficits. While Toronto with its 19.35 out of 28 and a winning record has been winning decisively and losing as equally decisively, as their low percentage indicates goals scored when the differential in score is relatively high.
Marc Foster is a research analyst in Fort Worth, Texas. Chris Apple is a database analyst/Internet specialist in Lincoln, Neb. Together, they operate HockeyResearch.com, and hope to one day elevate statistical research in hockey to the level seen in other sports.