It may not seem a good time to be predicting relegation for Reading (just after they’ve beaten us), QPR (buoyed by big new signings with an escapologist in charge) and Aston Villa (didn’t we somehow contrive to make even them seem half-decent?). But John McCormick has been pottering around with his blinding statistictal science again, attempting to calculate the impact fluctuating goal differences can have on survival prospects. As things stand, he sees safety for Sunderland but not by a comfortable margin and a possible lifeline for Reading, at Wigan’s expense …
A few weeks ago (December 30: https://safc.blog/2012/12/mccormicks-craic-spot-the-difference-in-the-relegation-dog-fight) I posted something about goal differences in which I wrote:
“I think it’s safe to say the teams from the bottom which will avoid relegation are those whose goal differences show the greatest improvement”
This is the chart I used at the time to show how our goal difference was doing:
Since then we’ve played at most six games, so it’s early days, but this is the current position:
The downward trend is continuing as we are losing as many games as we are winning but, as before, it isn’t falling off a cliff. We got walloped by Liverpool but recovered with a 3-0 win over West Ham, since when we’ve picked up a few points and moved away from the relegation zone, despite some surprising results from those whom I said were doomed at Christmas.
But you’ll remember what I said at the top of the article, it’s the teams which have the greatest improvement which will avoid relegation. So how do we compare with the other clubs in the mire?
“Not badly” is the answer.
The New Year posting compared us with Wigan, Villa, Reading, QPR, the Mags and Southampton, the bottom clubs at the time, and I included Fulham as they had had a run of iffy results. Here are their goal differences since the start of the season:
QPR and Reading were the bottom two and looking likely candidates for the drop, so I made this prediction about the six others:
“I’m going to stick my neck out and say that the five whose goal differences show the greatest improvement in the second half of the season will avoid relegation, irrespective of their points on Boxing Day, and a consistent decline will point to the doomed team.”
You can see where Villa had two horrendous weeks but other than that it’s difficult to see from the chart who has shown the least or the most improvement since the New Year. To get a clearer picture I did a little playing around with a spreadsheet to reset goal difference to zero at the halfway stage, ie at game 19 for all of the teams, and then recalculated goal differences until the end of January.
You can see the results in the next chart, which shows changes in goal difference since game 19. As I had already consigned QPR and Reading to relegation I have taken them out to simplify the picture; maybe events will prove I acted too hastily. As I’m looking for a third candidate I hope Reading and QPR fans will forgive me and read on:
This chart shows NUFC and Villa were both in decline but NUFC’s goal difference now appears to be heading upwards. Sunderland’s 3-0 defeat and 3-0 win show up as a dip but after that their line doesn’t move up and down much, which is not surprising as we haven’t won or lost by more than one goal since West Ham. Fulham’s goal difference stays within a narrow band, as does Southampton’s. Wigan’s goal difference appears to show as much variation as Sunderland’s, their graph has a mirror-image look to ours, but they are actually not doing as well as we are.
The chart wasn’t particularly helpful so I generated a trendline for each of the lines. You can see the results below. It transpired the trendlines could be put into two groups. Villa’s and Wigan’s goal differences are heading downwards. So too are NUFC’s, slightly less steeply. Sunderland’s, Southampton’s and Fulham’s lines are more or less level (ours is heading slightly uphill but our goal difference has actually declined by 1 since game 19. I’ll come back to this later).
If my original premise about a consistent decline in goal difference in the second half of the season is correct then one of the clubs showing this trend, ie Villa, NUFC or Wigan, are destined to become the third team to go down.
There are two caveats, however, and they are both important. Firstly, this is a very small number of games, especially as changes in January need to be accommodated – new players and even a new manager need to bed in – and small samples do not make for good predictions.
Secondly, I looked at something called the coefficient of determination (R2) for each of these trendlines.
R2 gives an idea of how close a trendline is to all of the actual points on the graph. An R2 value can be anywhere between 0 and 1 and the nearer it is to 1 the better is the fit. (If the R2 was 1 then the trendline would go through all of the points on the graph).
The Sunderland trendline had an R2 value of 0.02, which might explain why a decline in goal difference could be represented by an uphill line. The R2 value for NUFC was about 0.35 and for Wigan it was 0.5. Only Villa’s R2, at just over 0.8, supports the notion that their trendline is reliably indicating where their goal difference is heading, and I’m sure there will be mathematicians who want to disagree with me about even that.
Nevertheless, at the time of writing what we see at the bottom of the league table is reflected in the goal difference and trendline charts. If I did have to use them to make a prediction I’d say it is Villa who will go down and Wigan who will join them if Reading manage to stay out of trouble.
Am I confident about this?
Let me put it this way: I’m reasonably confident we’ll be safe but I won’t breathe easily until we get 42 points (and I don’t expect more than 43 for the season) or three other clubs are certain to finish below us – after all, this is Sunderland we’re talking about. I’ll revisit goal difference in another month or so and we’ll see if my prediction is still holding true and, if necessary, I’ll put the lines for Reading and QPR back in, with an apology.
** And if all those charts and statistics leave you in need of light relief, try Monsieur Salut (and lately Pete Sixsmith’s) Sunderland pages at ESPN. Latest posting: The Loneliness of the Long-Distance Supporter, at this link: http://soccernet.espn.go.com/blog/_/name/sunderland/id/1046?cc=5739#
Sample:
I know pilots sometimes announce important sports results but somehow sensed it was not going to happen (with Saturday’s game at Reading). The airline toilets may not be fitted with the equivalent of smoke detectors to trap clandestine use of mobiles – “the checking of football scores is strictly against international aviation regulations” – but you do get the impression it would be frowned upon.
I think QPR are looking healthier under Redknapp but still will go down. They just lost Remy for 2 months. Thats a huge blow. They’ve got no natural goalscorers in the team.
Newcastle have hit a vein of form and with their new signings, look like they will crawl up the table. They may even finish (God forbid) above us. I thought their new signings would not gel so quickly but it looks like I was wrong.
Reading have changed the way they play and look stronger.
Villa look the most likely to struggle.
And we too, look like we need a couple of wins under our belt before I can whisper the word “safety”.
Here’s my bottom three:
VILLA
SOUTHAMPTON
QPR
With Wigan to guarantee safety on the last day of the season (as per).
The Toon now have a full international at every position in the team. The January transfer window has transformed them:
Santon (Italy, left back)
Colocini (Argentina, Centre Half)
Mbiwa (France, Centre Half)
Debuchey (France, right back)
Cabaye (France, Midfield)
Tiote (Ivory Coast, Midfield)
Guiterrez (Argentina, Midgield)
Sissoko (France, Midfield)
Ben Arfa (France, Midfield)
Cisse (Senegal, Striker)
No-one there from the NE? No wonder we’re getting comments from geordiedoonsooth. That’s probably where they all are.
there’s no british players in there either, and I think that “midgield” is probably the best place for Guiterrez (sic)
Geordies either doon sooth or playing for your lot 🙂
How eminently sensible: play for us or emigrate but don’t stay in Newcastle.
So that’s why all your places live & go out in Newcastle not the arsehole of the world that is Sunderland
Are you only playing with 10 now?
Hasn’t Tim Krul been capped for Holland?
Really good article. Only question – you seem to be consigning QPR and Villa to relegation with Reading or Wigan going down, according to your headline. But in the article it seems that you are dismissing Reading and QPR – which way around is that meant to be? Otherwise, great analysis. Very interesting. For what it’s worth I don’t think we’re out of it yet (Reading – it won’t be easy, though) and I think Southampton are very much back in the mix as are Norwich (a slide almost as big as ours in 2007/08).
Good luck for the rest of the season
My headline, John’s analysis but that’s how I read it: QPR and Villa being his two main choices and Wgan to fill the third place if Reading escape
I think my confusion is mainly as we drop off the charts. Its a really interesting article, will see how this develops. Matthew
When I first started to look ad GD it was around Christmas and Reading were the bottom club. You know what they say about the bottom team at Christmas. After Boxing Day (if my memory is correct) QPR were bottom. That accounts for two teams and I haven’t done much to include them in the analysis as my focus was on who would join them – which of the five or six others wouldn’t pick up?
To date it’s Villa. But Reading’s trendline is pretty much horizontal. They could emulate West Brom and stay above Wigan, and no club is safe.
I do think QPR are doomed. Their trendline is still pointing downwards and while they have picked up points I think it’s not as many as the other clubs (except Southampton?) and the gap looks too much.
I might add I’m not desirous of any club’s relegation, I just want SAFC to stay up and Boro’ to come up
In three or four of the last six seasons one club has dropped like a stone. I think that this season only three clubs in the bottom half of the table have not gained either six or seven points from the last five games. Reading gained thirteen and Villa and and Norwich three each.
So you could be right. Keep an eye on Norwich, but I do think their manager is up to the task of ensuring they stay up.
We are coming to get you we are only 2 points behind now can’t wait for the big derby. The Toon to finish 10th S*nderland to finish 12th