WEEKDAY-ONLY POLLING AND PARTISAN SUPPORT LEVELS: EVIDENCE FROM NEW ZEALAND

Some scholars have argued that opinion polls conducted only on weekday evenings are likely to be biased in favour of right-wing parties, but there is no scholarly consensus on this. This paper presents evidence from New Zealand suggesting that weekday-only polling consistently increases the reported support levels for right-wing parties. Polls conducted only on weekdays in New Zealand give estimated support levels for the major right-leaning party approximately five percentage points higher than do concurrent polls that survey voters both on weekdays and during the weekend. Results for left-leaning parties are also broadly consistent with this effect.