Accredited official statistics announcement

How ONS assesses statistical outputs for residual seasonality

Seasonal adjustment is a fundamental analytical output in the production of high quality, internationally comparable economic statistics and underpins many of ONS’s most widely used economic series. ONS has significantly expanded its focus on assessment of residual seasonality in recent years and it plays an important role in maintaining the integrity of seasonally adjusted outputs. We describe how ONS assesses residual seasonality as part of its production process.

These statistics will be released on 12 May 2026 9:30am