“Seasonal adjustment” is a complex statistical procedure used to estimate the effect of the calendar on time series, and to deduct that effect from the series. Applying this procedure to time series data—economic and financial—helps in reaching more accurate conclusions regarding economic developments. The Information and Statistics Department at the Bank of Israel makes seasonal adjustments to many time series, and some of them are published on the Bank’s website.
Seasonally adjusted time series are used, among other things, as input for economic models and leading indicators of the business cycle and the state of the economy, and are an important element in the decision-making process by monetary policy makers.
This paper is intended to expand and deepen knowledge on the issue of seasonal adjustment, and to demonstrate the Bank of Israel’s implementation of it on the series of data on new mortgages taken out.