## Beating Save Percentage to Death Part 2: Year

I've looked at even strength save percentage for all goalies from 1997-2010. The data for 1997-1998 for special teams on the NHL.com web site has been fixed and I am now including it. In part 1 I looked at goalie age and even strength save percentage. In part 2, I look at the trend of even strength save percentage over time.

### Unweighted

A first look at the relationship comes from unweighted data. Each goalie is one data point, whether he played 1 game or 80. Here is the scatter plot:

### Model Summary

 R R Square Adjusted R Square Std. Error of the Estimate .03 .00 .00 .04

Sum of Squares

df

Mean Square

F

Significance

Regression

.00

1

.00

1.09

.30

Residual

1.27

1033

.00

Total

1.27

1034

B

Std. Error

Beta

t

Significance

(Constant)

.31

.57

.00

.54

.68

Year

.00

.00

.03

1.04

.30

Not a lot there.

### Weighted

We can rerun the regression, using shots faced as a weighting factor. The scatter plot of the means does look promising:

And there is a significant relationship.

### Model Summary

 R R Square Adjusted R Square Std. Error of the Estimate .61 .38 .38 .00

Sum of Squares

df

Mean Square

F

Significance

Regression

0.0000

1.0000

0.0000

6.0317

0.0339

Residual

0.0001

10.0000

0.0000

Total

0.0001

11.0000

### Coefficients

B

Std. Error

Beta

t

Significance

(Constant)

0.06538

0.35000

0.00000

0.19000

0.88000

Year

0.00043

0.00020

0.61340

2.45600

0.03390

So not a huge effect from year to year, but over the 12 years the predicted average even strength save percentage does go from 0.914 to 0.919. As an aside, the 1997-1998 data put this over the hump in terms of statistical significance. Looking at the trend in overall save percentage, I suspect that, if we go back further, the trend continues. If anyone has the data from the years before 1997 and would like to make it available to me I would be deeply appreciative. If not, I can see if I can construct it myself.

### Conclusion

There is a statistically significant relationship between year and even strength save percentage.

If this FanPost is written by someone other than one of the blog's editors, the opinions expressed in it do not necessarily reflect those of this blog or SB Nation.

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