1332.0.55.002 - Statistical Language!, 2008

ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 27/06/2008 First Issue

Page tools: Print

Print Page Print all pages in this product

Contents >> Time Series >> Why are Time-series Seasonally Adjusted?

WHY ARE TIME-SERIES SEASONALLY ADJUSTED?

Time series are seasonally adjusted as seasonal effects can conceal both the true underlying movement in the series, as well as certain non-seasonal characteristics which may be of interest.

Example of a Seasonally Adjusted Time Series:

Total Overtime for Employees of 'The Widget Company' 2006-2007, Seasonally Adjusted
Graph: graph time series 2

time series arrow
Diagram: time series

The time-series has been adjusted to remove the sharp increase in the amount of overtime worked in December, which is attributable to the increased demand for Christmas Widgets over the Christmas season. The series has not been adjusted for irregular or one-off affects, which have the potential to mask underlying trends.