60f18ee3_m_to_produce_different_figures__Methodology_comparison
[YouGov] No. [ICM] This is the so-called “spiral of silence adjustment”. ICM allocates half of those who will vote but “don’t know” to the party they said they voted for last time. This increases the overall voter “pool” thus diluting the standard responses. [Methodology comparison] 
The “will vote won’t says”
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 ”
politicalbetting.com » Blog Archive » Why YouGov and ICM seem to produce different figures
Methodology comparison