USA retail sales and trend estimates for August 2015

It has been a long time since we’ve looked at the USA Retail Sales estimates. Way back in 2012: http://www.seasonaladjustment.com/2012/09/14/usa-retail-sales-for-august-2012-and-the-trend/ so it is worth a revisit.

The Census Bureau do not estimate or publish official trend estimates, but trend estimates can be derived by taking the published seasonally adjusted estimates and applying a set of Henderson filters (with a bit of code in R and ggplot2). Using the latest published data up to and including August 2015 gives

USA Retail Sales Seasonally adjusted and trend estimates

where the one month percentage change in the trend and seasonally adjusted estimates are

Dec 2014 Jan 2015 Feb 2015 Mar 2015 Apr 2015 May 2015 Jun 2015 Jul 2015 Aug 2015
Trend -0.24 -0.18 -0.01 0.26 0.49 0.58 0.53 0.45 0.36
Seasonally adjusted -0.87 -0.77 -0.53 1.54 0.03 1.18 -0.04 0.71 0.19

So underlying one month movement in the trend has been strong since March 2015 even though the seasonally adjusted one month movements have bounced around. Even with a dip in the seasonally adjusted estimate in September 2015, it shouldn’t change the fundamental view of the underlying strengh in recent periods.

Over the length of the series the median for the one month percentage change in the trend for USA retail sales is 0.4%, so the recent activity is back in line with historical growth.

For background you can get the seasonally adjusted data here: http://www.census.gov/retail/marts/www/timeseries.html

Seasonally adjusting Greek retail sales

Today the Greek retail sales were released and it made some headlines with

“…evidence that Greece’s economy is still contracting – Greek retail sales tumbled by 12.1% in September, compared with the previous year. That follows a 9.3% decline in August, showing that the slump actually picked up pace.”

The actual data can be obtained from the ELSTAT website although it doesn’t seem that the seasonally adjusted estimates are made available. This probably explains why the news reports focused on the 12.1% fall between September 2011 and September 2012. But having downloaded the original data we can apply seasonal adjustment (and also calculate trend estimates) by using X-13-ARIMA and see if this changes the interpretation of the most recent data. Plotting this shows…

Greek retail sales to September 2012

Some interesting observations.The year-on-year change in September is -12.1% in the original data for September (as reported), but once seasonality is taken into account (e.g. in this case the changing seasonality over the years), this is -11.9% over the year. Calcuating a trend estimate gives the underlying change over the last year of -10.4%.

Having derived the seasonally adjusted and trend estimates this can give us a better indication of what is happening at the current end of the series. While the month-on-month trend changes are still decreasing in the recent six months, the latest data shows a -1.1% change in the trend between August and September 2012. This is a much better indicator of what is going on now than looking at the year-on-year change in the unadjusted data.

Interesting, the plot also shows that the December seasonality is reducing quickly over the last few years. This is more easily seen by looking at the seasonal plot for December below. I have also included August and September data. Some of the downwards monthly movement that is seen for September 2012 can be attributed to the higher than normal August estimates, as the September 2012 data came in pretty much inline with historical September estimates. So perhaps the recent Retail activity is starting to level out.Greek retail sales seasonal and irregular chart