Annual seasonal adjustment and workplace denominators revisions

The seasonally adjusted claimant count and Jobseeker's Allowance series were updated at 09:30 on 17 June 2015 to include results from the latest annual review. The series has been been revised back to January 2012. The datasets updated are:

• Claimant Count - seasonally adjusted
• Jobseeker's Allowance flows - seasonally adjusted
• Jobseeker's Allowance seasonally adjusted

All other Jobseeker's Allowance datasets on Nomis are not seasonally adjusted so are not affected by these revisions.

At the same time the workplace-based denominators used to calculate national and regional claimant count rates have been updated with new 2014 estimates and revised back to January 2012.Rates from January 2014 are now based on mid-2014 denominators.

Seasonal Adjustment Background

The claimant count series, like many time series, are difficult to analyse using the raw data because short-term movements are dominated by seasonal effects. The series are therefore seasonally adjusted by identifying and removing the seasonal component, leaving the trend and irregular components.

The monthly seasonally adjusted Jobseekers Allowance series include stocks, inflows and outflows for males and females at national and regional level only (no local authority data).

Every year, the seasonal adjustment of the claimant count is reviewed. This involves looking at each series individually to determine the type of adjustment to be used, identify the seasonal pattern, and investigate any other effects in the data that are not strictly seasonal.