Wednesday 4 September 2013

Poll - 39.7% Yes, 41.4% No, 18.9% DK

There was a poll…
A rare poll, a rattling poll…
A poll down indyref-ee-oh

So, see that TNS-BMRB poll that gave such surprising results?  There were lots of comments about how it wasn’t weighted to the 2011 election results given that the question was asked.  One chap, a certain Professor John Curtice, said:

“Still, here perhaps we should enter another small word of caution. Unlike either YouGov or Panelbase, TNS do not weight their results so that their respondents’ reports of how they voted at the last election (the 2010 UK election in the case of YouGov, the 2011 Holyrood contest in Panelbase’s case) more or less match the actual outcome of that election. However TNS did actually ask their sample how they voted in 2011 – and found that rather fewer said they voted SNP than indicated they backed Labour. Such a divergence from what actually happened in 2011 is bound to raise questions about whether TNS’s sample adequately reflects the nation’s political balance.”

So I thought I’d do a wee calculation to weight it the way that Panelbase weights it and the result is Yes 39.7%, No 41.4%, Don’t Know 18.9%.

Before anyone feels the blue touch-paper burning their bum, this isn’t the way to weight a poll properly; it’s just a calculation for my own amusement.  Also, there are some parts of the calculation that I’d criticise if anyone else did this calculation (feel free to tell someone).  Here’s how I did the calculation with instructions for you to follow if you’re exceedingly bored –


2.      Go to Table 1 on Page 3

3.      Copy the weighted numbers against the parties in the end box (Vote in 2011) – ignore “Can’t remember” and “Did not vote” because those who can’t remember probably didn’t vote and people who didn’t vote in 2011 are least likely to vote in 2014 and the two categories together add up to 42% against the 2011 turnout of 50% (if I remember rightly).  That, and it made the calculation all watery (I don’t have the raw data, just the tables).

4.      Note that there is no vote percentage there for Green, SSP, Solidarity or any party not in the big three plus the Lib Dems – they must all be included in “Other”.

5.      Calculate what percentage those numbers translate to in terms of party share (SNP comes out at 36.5%, for example).

6.      Compare that to the actual 2011 result to get a ratio.

7.      Use the ration to change the numbers to what they would be had it been weighted to the 2011 result.

8.      Bob is no longer your Auntie but is now showing the contest neck and neck – hoopla!

9.      There are plenty caveats but you can work them out for yourself.

Here’s a wee table (just copied from my spreadsheet) -


poll
%
Yes
No
DK
2011 const
Yes
No
DK
SNP
215
36.50
119
42
54
45.39
148
52
67
Lab
231
39.22
32
149
49
31.69
26
120
40
Con
58
9.85
3
48
7
13.91
11
68
10
LD
68
11.54
8
48
13
7.93
82
33
9
Oth
17
2.89
2
11
4
1.5
1
6
2

589





268
279
128







39.71026974
41.37094892
18.91878134


If you want even more fun, use the unweighted figures and you get even closer – 40.1% Yes, 41.1% No, 18.8% Don’t Know.  Here’s the table:


poll
%
Yes
No
DK
2011 const
Yes
No
DK
SNP
230
39.05
119
42
54
45.39
138
49
63
Lab
249
42.28
32
149
49
31.69
24
112
37
Con
63
10.70
3
48
7
13.91
10
62
9
LD
69
11.71
8
48
13
7.93
81
32
9
Oth
18
3.06
2
11
4
1.5
1
5
2

629





254
261
119







40.07452711
41.11113968
18.81433321


Next week I’m making a submarine out of a sponge and a bar of soap.

2 comments:

Hootsman (still) Banned Me said...

Good Stuff , Cheered me up no end to know and understand the misinformation and P*Sh being peddled by Project Fear, that even I cannot distinguish without help.

Jim Monaghan said...

I dont understand dwhere you get the high YES votes from Lib Dems?