Each data series is indexed to a start date of average purchases in that consumption category in February 2020 (= 100) i.e. prior to the first lockdown restrictions in the UK. The figure for any particular day represents a backwards-looking seven day rolling average (reflecting that these payment flows are volatile on a day-to-day basis, but follow regular weekly patterns).
Benefits and limitations of the series
The key benefit of the series is that it can provide a near-real time tracker of retail purchases, and how spending (overall, and in each of the categories) changes in the short term as e.g. Covid-related restrictions are tightened or loosened – which can often affect different sectors to different degrees (or cause substitution effects between sectors). However, these data series do have a number of limitations and drawbacks, which are explained below.
There is no seasonal adjustment of the series, and there is also no adjustment for the longer term effect of card payments representing an increasing share of all payment methods. As such the series is better suited to observing short-term changes rather than long-term trends.
These series only identify a subset of major UK retailers; currently around 100 in total. In particular, these CHAPS-based data series can only ever cover the subset of retailers whose merchant acquirers use a different payment service provider (PSP) (such as a bank) to themselves. Where the retailer and merchant acquirer use the same PSP, including where the PSP itself provides merchant acquiring services directly to the retailer as part of a package of banking services, the transfer may be internalised within the PSP’s own books with no payment is made to the retailer across the CHAPS system.
The sample of retailers captured in the series changes over time. Card acquiring is a competitive business and retailers will typically retender or reorganise their merchant acquiring services every few years. Merchant acquirers may also change how they pay retailers the proceeds of card purchases: for example, using an alternative UK payments system. As such, the retailers that receive daily CHAPS payments from merchant acquirers changes relatively frequently.
During the course of 2020, 30 retailers were excluded from the sample as they no longer received daily payments from their acquirer via CHAPS, and 32 retailers were added to the sample as they started to receive daily payments from their acquirer via CHAPS.
- When an observed relationship ceases (i.e. no payments observed for at least three consecutive working days, with no other explanation, such as the impact of new lockdown restrictions on the sector), the retailer is removed from the sample. For this reason, the data are calculated with a three-day lag. This enables us to remove retailers from the same before they erroneously reduce aggregate purchases for their sector. Thereafter, changes in the index score for that sector are calculated based on the changes in the levels of purchases at the remaining retail corporates in the sample.
- Likewise when a new relationship is observed (a new flow of daily payments are observed for at least thirty working days with total observed card purchases of at least £5m a year), they are added to the relevant retail sector.
Changes in the retail sector thereafter are calculated based on changes in the level of purchases at all firms now included in the sector. There is no backwards revision to the data; we do not therefore include the 30-days’ worth of payments the retailer needed to have first received in order to be included in the series.
The Bank is unable to publish data by retail sector because some of the sectors feature fewer than three retailers within our sample and/or may be at risk of becoming fewer than three retailers if an observed relationship ceases in the future.
Other similar series available
A number of other entities provide indicators of UK spending on credit and debit cards using data from transactions across their systems, for example Barclaycard and Visa. These other data sets may be based on a more comprehensive data set than the Bank’s, and may incorporate adjustments to reflect longer term structural changes. The richer data set means that those series may be more reliable indicators of retail activity, both in the short term but especially in the longer term. However, the Bank is able to make its experimental series available for the public ONS faster indicators weekly release. Please be aware that both the Bank’s Monetary Policy Committee (MPC) and Financial Policy Committee (FPC) have access to similar data from other sources / data providers, and consider trends across all sources of data. Thus these experimental data series should only be considered indicative of the broader set of UK retail purchase data available to the MPC and FPC.