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Sample

Despite extensive efforts to reach out to all demographics, the sample collected was not representative of Portsmouth’s known population. In order to ensure that the results of the analysis were representative of the views of the city’s residents, the data was weighted using various sources of Official Statistics (see table below) based on the following variables: age, gender, ethnic group, disability and postcode district.

The weighted sample, where base sizes allow, provides a robust dataset from which Portsmouth City Council can base decisions on, confident that the data represents the views and opinions of the city’s residents as closely as possible within the parameters of the sample collected.

 

Weighting

A Random Iterative Method (RIM) weighting was applied to the data. This ensured that each demographic was accurately represented.

The target demographics were taken from a recruitment methodology paper written by Portsmouth City Council and externally verified. Details of the source of each dataset used to understand the breakdown of the population of Portsmouth within each strata are presented in the table below

*due to the small numbers of responses we received in specific ethnic minority groups, we have combined ethnic minorities groups for the data weighting process.

wdt_ID Strata Dataset source Link
1 Age ONS 2021 Census https://www.ons.gov.uk/datasets/create
2 Sex ONS 2021 Census https://www.ons.gov.uk/datasets/create
3 Ethnic group* ONS 2021 Census https://www.ons.gov.uk/datasets/create
4 Disability ONS 2021 Census https://www.ons.gov.uk/datasets/create
5 Postcode ONS 2021 Census https://www.ons.gov.uk/datasets/create
wdt_ID Strata Original sample Weighted sample
1 Males 38% 51%
2 Females 62% 49%
3 - - -
4 Aged 16-24 years 2% 19%
5 Aged 25-34 years 11% 18%
6 Aged 35-44 years 16% 16%
7 Aged 45-54 years 17% 15%
8 Aged 55-64 years 24% 14%
9 Aged 65+ years 32% 18%
10 - - -
11 Disability 26% 20%
12 No disability 74% 80%
13 - - -
14 White 97% 86%
15 Ethnic minorities 3% 14%
16 - - -
17 PO1 12% 15%
18 PO2 20% 20%
19 PO3 11% 10%
20 PO4 30% 20%
21 PO5 15% 14%
22 PO6 13% 20%