ICM takes polling honours

		By David Cowling Editor, BBC political research

Some 29 voting intention polls were published throughout the 2001 campaign.

Two of them (both by Rasmussen) registered the actual Conservative share of 33% at some stage in the campaign; only two registered the 19% share achieved by the Lib Dems; and every single poll put Labour above its 42% share.

The table below records the range of voting intention figures for the five polling companies throughout the campaign:

	Lab range	Con range	LD range
Gallup	47-48	30-32	13-18
ICM	43-48	28-34	14-19
Mori	45-55	26-31	11-18
NOP	47-49	30-32	13-16
Rasmussen	44-46	32-33	13-17
Result	42	33	19

The fluctuations were less marked this time compared with 1997.

Whereas in 1997, four out of five polling companies put Labour at 50% or more at some stage in the campaign (compared with the party's eventual 44% share of the vote) this time only one out of five companies did so.

Of Mori's eight published polls, six put Labour on 50% or more.

Mori changed its methodology towards the end of the campaign and as a result cut Labour's share by an extraordinary 7% and increased the Lib Dem share by 5%.

The company claimed that this simply repeated what itdid in its final poll of the 1997 campaign, but the difference then was utterly negligible. Gallup also changed its methodology during the 2001 campaign, but the difference that resulted was only 1% in the Conservative share.

Robert Worcester of Mori published some highly sceptical remarks about the methodology of Rasmussen, but the latter emerged with a. better record than his own company.

The final test

However, the traditional test for the pollsters is their final published poll. So, what was the record for 2001?

The relevant polls are set out in the table as well as (in brackets) how far they diverged from the real result:

	Con %	Lab %	LD %	Lab lead %
Gallup	30 (-3)	47 (+5)	18 (-1)	17 (+7)
ICM	32 (-1)	43 (+1)	19 (0)	11 (+1)
Mori	30 (-3)	45 (+3)	18 (-1)	15 (+5)
NOP*	30 (-3)	47 (+5)	16 (-3)	17 (+7)
Rasmussen	33 (0)	44 (+2)	16 (-3)	11 (+1)
Result	33	42	19	9

* NOP polled for the Sunday Times and therefore its final survey was sampled between 31 May-1 June.

ICM's final poll for the Guardian came the closest to the final result. It gave the Dem share exactly, understated the Tories by 1% and overstated Labour by just 1%.

Exit polls

Two exit polls were conducted throughout 7 June: by NOP for the BBC and Mori for ITN. At 10pm the two predictions were:

	Actual	BBC	+/-	ITN	+/-
Lab seats	413	408	-5	417	+4
Con seats	166	177	+11	154	-12
LD seats	52	44	-8	58	+6
Lab majority	167	157	-10	175	+8

Both polling companies therefore provided their respective clients with remarkably accurate forecasts.