Methods

• Data collected during monthly household survey beginning October 2020
• Each month involves a new representative sample of ~ 450 adults (16 and over)

Due to the pandemic:

• Surveys are conducted by telephone and among adults aged 18 and over until face-to-face collection is possible
• From April 2020 (switch to telephone), Ipsos started recording ~<5% cases as missing for social grade. To derive weight variable (which uses social grade), Ipsos assumed missing = social grade C1. To ensure analyses using weight and social grade reflect target weighed profile, social grade was recoded to reflect this assumption. Different assumptions for missing social grade cases were explored in a parallel telephone and face-to-face (with no missing social grade) wave, and this assumption found least distorting.

Methods described in open access: Kock L, Shahab L, Moore G, Beard E, Bauld L, Reid G, Brose L, Horton M, Gould A, Brown J. Protocol for expansion of an existing national monthly survey of smoking behaviour and alcohol use in England to Scotland and Wales: The Smoking and Alcohol Toolkit Study. Wellcome Open Research. 2021 Mar 29;6(67):67.