Seasonal variation

Japanese: 季節変動 - きせつへんどう（英語表記）seasonal variation

Seasonal fluctuations are seen in time-series economic statistics. They are generally caused by natural phenomena such as weather, social systems, and customs. In Japan, typical seasonal fluctuations are most evident in statistics on companies, wages, and finance during the fiscal year-end and bonus periods in March and September, but time series that regularly fluctuate over shorter periods such as three months or one month can also be treated as seasonal fluctuations. The seasonal fluctuations of time-series economic statistics are indexed as seasonal indices, and are usually expressed by indexing the seasonal fluctuations of the quarterly or monthly data for the relevant period, with the average of quarterly or monthly data set at 100. Seasonal indices are sometimes used for the purpose of analyzing seasonal fluctuations themselves, but are usually used to remove seasonal fluctuations from time series. In economic analysis, if such seasonal fluctuations are not removed, the trend fluctuations of the time series are often lost, and time series with such seasonal fluctuations removed are called seasonally adjusted values.

Source: Encyclopaedia Britannica Concise Encyclopedia About Encyclopaedia Britannica Concise Encyclopedia Information

Japanese:

時系列の経済統計にみられるもので，季節的な原因によって引起される変動。一般に天候などの自然現象，社会の制度，慣習などに起因する。日本の場合には典型的な季節変動が3月，9月の決算期やボーナス期の企業，賃金，金融関係などの統計の動きに強く現れるが，このほか3ヵ月や1ヵ月といった，より短い期間で規則的に変動する時系列も季節変動と同様に扱うことができる。この時系列経済統計の季節変動を指数化したものを季節指数といい，通常は四半期データまたは月別データの1年間の平均を 100として，それぞれ当該期の四半期ないしは月別データの季節変動を指数化して表わす。季節指数は季節変動自体の分析目的のために用いることもあるが，通常は時系列の季節変動を除去するためにこれを利用する。経済分析に際してはこうした季節変動を除去しないと，当該時系列の趨勢変動が見失われることが多く，こうした季節変動を除去した時系列を季節調整値と呼んでいる。

出典　ブリタニカ国際大百科事典小項目事典ブリタニカ国際大百科事典小項目事典について　情報

<<: Xenia - Kisenia (English spelling)

>>: Monsoon climate - kisetsufuukikou