Note on sample sizes

At Fairer Finance, we are always looking to improve our methods to make our ratings as up to date and representative as we can.

Every six months, we get 10,000 responses in our banking and insurance surveys, supplied by the independent polling company Opinium, to assess customers' feelings of Happiness and Trust for each brand in our ratings.
Each set of customer experience ratings, published in Spring and Autumn each year, includes six polling cycles, or three years' worth of survey responses.

The responses are weighted so that more recent responses count for more. The weighting is as follows:

• Most recent wave of the survey - 40%

• Previous wave - 25%

• Previous wave+1 - 15%

• Previous wave+2 - 10%

• Previous wave+3 - 5%

• Previous wave+4 - 5%

There is some persistence of respondents from wave to wave of the survey. On a typical bi-annual tracker, with waves run every six months, Opinium would generally expect around 35%-40% of the total sample to have also answered the previous wave's survey.

The minimum sample size threshold is set at 41 responses across the last six waves of the survey, so as to only include providers in the ratings with enough responses to be informative. Users can filter the results by sample size, if they wish to only see the results for larger providers.

We publish the sample size for each of the metrics we calculate, only some of these contribute to our ratings. These numbers may vary as some of the calculations (e.g. Communications ease of understanding) are newer than others (e.g. Happiness or Trust).