NEW YORK (April 20, 2010) – Retail sales rose for the fifth consecutive week despite facing a post-Easter seasonal drag. Overall sales improved by 0.2% on a weekly basis according to the ICSC-Goldman Sachs weekly sales index for the period ending April 17. On a year-over-year basis sales remained strong (+4.6%).
“Helped by seasonably-warm temperatures for the week, customer traffic—especially at department and apparel-specialty stores—improved over the same week of the prior year,” said Michael Niemira, ICSC director of research and chief economist.
“However, with about 4-5 percentage points of March’s monthly sales lift due to the Easter calendar shift, the April ‘echo’ will depress store sales somewhat. As a result ICSC Research continues to expect that April sales will be flat to down 3%,” Niemira added.
The Weekly Chain Store Sales Snapshot is produced by the International Council of Shopping Centers and Goldman Sachs.
This index measures U.S. nominal same-store or comparable-store sales excluding restaurant and vehicle demand. The weekly index is constructed as a sales-weighted geometric average growth rate to preserve long-term consistency and is statistically benchmarked to a broad-based monthly retail industry sales aggregate that currently represents approximately 40 retail chain stores, which also is compiled by ICSC. A representative sample of those major retailers has been used as a control group to extrapolate the weekly sales index.
As such, the weekly index statistically represents industry sales and is not just a sum of sales for a handful of retailers.
The standard period used for the index is Sunday through Saturday, even though some retailers use a different weekly accounting period. The weekly sales index is presented on an adjusted basis to account for normal seasonality and to counter other data anomalies.
Weekly seasonal adjustment is at best difficult for chain store sales given that retailers can and often do shift promotions to counter typical shifts in the calendar. Nonetheless, the approach to weekly seasonal adjustment used follows from the Piser Method, which was popular in the early 1930s and became the standard for weekly adjustment.