morley pie eater wrote: ↑Mon Mar 20, 2023 8:10 pm
Let me introduce myself by way of explanation. I was a Maths teacher, I taught A-level Maths and Further Maths for 20 years. Though I'm retired, occasionally I get the urge to get my pen and paper out and do a few calculations.
I'm not boasting about my qualifications, but thought I may need to set the scene for what follows.
A recent poster claimed (as others have) that we need a 9 who runs from dummy half more, as not doing makes us too predictable. Above is my first response, but once I start on statistics, I like to do it proper.
To be fair and accurate, I needed stats for a full season as, with only 5 games played this year, results could be skewed by who has played who. So I took the 2022 season's figures. I compared a "league table" based on how many dummy runs each team made, with their actual league position at the end of the 2022 season.
With me so far? Right, here we go:
Posn . .Team . . DR . .League Posn.
1. Hull KR . . . .469 . . .8th
2. Warringt'n . . 316 . . .11th
3. Toulouse . . .313. . . 12th
4. Leeds. . . . .288 . . . .5th
5. Hudd'fd . . . .277 . . . .3rd
6. Salford . . . . .275 . . . .6th
7. Wakef'd . . . . 271. . . .10th
8. Hull. . . . . . 264 . . . .9th
9. Castlef'd . . . . 240. . . . 7th
10. Saints. . . . . .184. . . . .1st
11. Catalans. . . . .164 . . . 4th
12. Wigan. . . . . 137. . . . .2nd
This represents a "negative correlation", meaning that it is more likely that a team with a low number of Dummy Runs (DR) finished higher in the league, and a team with more DR finished lower.
It's easy to see this if you note that the 3 teams with least DR finished 1,2, and 4 in the league. Meanwhile Toulouse, with twice as many DR as these 3 averaged, finished bottom. Hull KR, who made a phenomenal 3-and-a-half times as many DR as Wigan, finished 8th.
I'm sure that every SL coach will be aware of these data. As Wayne Bennett said, “If you start listening to the fans, it won’t be long until you are sitting next to them.”
[Added notes for the technically minded:
1. Spearman's rank correlation coefficient, r = -0.60839.
r = 1 would indicate a perfect match, so the top team would have most DRs and the bottom team least etc.
r = -1 indicates a perfect negative match, so the top team has least DRs and the bottom team most.
2. The figure does not prove that there is a link. ie I'm not saying that doing more/less DRs makes you a worse/better team. For example, the negative correlation could be because top teams are more confident in their other plays and don't feel the need to run for dummy half quite so much. Or there may be no reason at all. The reasons for the link are for the experts to decide, but the link is clear.
What it does show is that there certainly ISN'T a positive link - that if you do more DRs you'll be a better team.]