Seasonal adjustment

…Seasonal patterns are often considered exogenous in economic analysis, and are often removed prior to analysis. There are two main methods for removing seasonal variations (this is called "seasonal adjustment," and the seasonally adjusted figures are called "seasonally adjusted values"). One is often used by government agencies that create economic data, in which the original series of the variable under consideration is divided by a moving average of an appropriate length to obtain a seasonal index, which is then adjusted so that the annual average is 100, and then applied to the original series to obtain a series from which seasonal variations have been removed. …

*Some of the terminology that mentions "seasonal adjustment" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…　季節変動のパターンは経済分析に際してしばしば外生的なものとされ，分析に先だって取り除かれることが多い。季節変動を取り除く(このことを〈季節調整seasonal adjustment〉，季節調整済みの数値を〈季節調整値〉という)方法は大別すると2種類ある。一つは経済データを作成する政府系機関等がよく用いるもので，考える変数の原系列を適当な長さの移動平均で割って季節指数を求め，さらにこれを年間平均が100になるように調整したうえで，原系列に適用することによって季節変動を除去した系列が求められる。…

※「seasonal adjustment」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報