Yet telephone surveys that include both landlines and cellphones “continue to provide accurate data on most political, social and economic measures” when weighted to match the demographic composition of the population, according to Pew.

In a report published this week the research organisation compared two surveys – one with a response rate of 9% and one with an enhanced response rate of 22% – to a range of government survey data, voter and consumer databases and each other.

Broadly, Pew found little differences between the surveys and the comparison data sets. But one “significant area of non-response bias” is in measures of volunteering and civic activity.

Pew said its survey participants tended to be significantly more engaged in civic activity than those who do not participate, suggesting that telephone surveys could lead to overestimates of behaviour such as church attendance, contact with elected officials and attendance at campaign events.

The full report is here.