Information Note on Implications of COVID-19 on the Retail Sales Index April 2020

Data for the Retail Sales Index (RSI) is collected monthly from a sample of 1,600 retail enterprises. Despite the current difficult circumstances, many retailers have continued to supply us with this information and we wish to thank all survey respondents for their ongoing support. 

However, due to temporary closure and the difficulties faced by businesses, the response rate for the April 2020 RSI was about nine percentage points lower than the corresponding month last year.

Imputation

The Retail Sales index is based on a matched sample of enterprises in consecutive months. Imputation is not normally carried out for smaller enterprises which have not returned data. In each sector key companies are identified based on their significance to the sector (turnover). If key company data is not received on time for the Provisional results, then an estimate is made using trends from other similar companies and other data available at the time.

The reduced response rate for April 2020 meant that a limited imputation of smaller enterprises was also carried out.  This occurred where the response for a sector or a cell (based on turnover size) was low.  Estimates for these missing smaller enterprises were made using the trends shown by responding enterprises in the same sector. In addition, where enterprises notified us in March that they were closed for several months, a turnover figure of zero was recorded for the month of April.

Auxiliary data sources have also been used to validate the results for April 2020 at retail business category level. The CSO is satisfied that this full range of information supports the trends estimated in the Retail Sales Index for April. The auxiliary sources used for imputation and validation included:

• Government communications on the list of essential services and outlets indicating when sectors shut down in March and remain closed
• Published media and research reports on the retail sector for the month
• Retailers’ websites, for information issued by non-responding companies about closure, continuation of trade, online trade etc
• Published data on credit card and debit card spending in April compared to other periods
• Data from other CSO outputs including vehicle licensing as a measure of car sales
• Sectoral data on the numbers availing of support schemes such as the Pandemic Unemployment Payment and the Wage Subsidy Scheme

Seasonal Adjustment

The figures for March and April 2020 are an exception to existing seasonal patterns. Seasonally adjusting the Retail Sales Index will be challenging until the scale and shape of the impact COVID-19 has on the time series is better understood.  The seasonal adjustment models were reviewed in April 2020 and changed as appropriate. Users should be aware that further observations, as data becomes available in the months ahead, and revisions to the seasonal adjustment models may result in revisions to the seasonally adjusted series.

Data Collection in April 2020

The majority of retail outlets were closed in April, with only a small number of sectors allowed to open their shops. While many sectors were closed, some turned to online sales, to generate turnover and provide a service to customers. A sample of outlets in closed sectors have reported some element of turnover, related to ancillary activities such as online sales, take-away food, off-licence sales etc..

The CSO wishes to thank all those enterprises who supplied their retail sales data for April and urge them to continue to do so for May and future months. Even if  turnover  is  nil or very low, such information is still needed to measure the trend in sales in each  retail sector. The CSO will also continue to monitor the range of supplementary information described above to derive the best estimate for retail sales in May. The May Retail Sales Index is planned for publication on 29 June.