60f18ee3_m_to_produce_different_figures__Methodology_comparison
[YouGov] To ensure balanced samples this is done by party ID based on the firm’s own data. This can be controversial – in almost every survey “others” -SNP/PC/UKIP/BNP/GRN – has to be scaled down very sharply so that on occasions those identifying with one of those parties can be worth barely a third of the norm. [ICM] ICM was the pioneer of past vote weighting so that samples are weighted according to a formula linked to the May 2010 election result. There is a corrective calculation to deal with “false recall”. [Methodology comparison] 
Political weighting
S a m p l i n g
P o l i t i c a l w e i g h t i n g
N e w s p a p e r w e i g h t i n g
T u r n o u t w e i g h t i n g
D i d n ’ t v o t e M a y 2 0 1 0
T h e “ w i l l v o t e w o n ’ t s a y s ”
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Methodology comparison