CSO publication, 28, 11am
| Compare price of item for this month with its price from previous month | - Individual Price Relative |
| Group items for each respondent into product groups | - Article Group |
| Calculate unweighted average of individual price relatives within article group using chained Jevons index. Divide this figure by the same figure for the previous month. | - Month-on-Month Article Group Index |
| Calculate weighted average of month-on-month article group indices for all respondents within a product group within a NACE category using chained Young index. Divide this figure by the same figure for the previous month. | - Month-on-Month Article Group Index |
| Calculate weighted average of month-on-month product group indices for all product groups within a NACE group using chained Young index. Divide this figure by the same figure for the previous month. | - Month-on-Month NACE Group Index |
| Apply month-on-month NACE Group Index to updated value for the NACE group from previous month. Divide this new updated value by the NACE group base period weight. | - Base Period NACE Group Index |
| Rescale the Base Period NACE Group Indices by dividing by the mean of the Base Period NACE Group Indices for Base Year 2021. | - Base Year NACE Group Index |
| For all higher levels, sum the updated values of the relevant NACE groups. Divide these aggregated updated values by the value for the previous month to get the Month-on-Month Index | |
| Divide the aggregated updated values by the base period weight to get the Base Period Index | |
| Rescale the Base Period Index by dividing by the mean 2021 index to get the Base Year Index | |