Seasonal adjustment methods in the time series analysis and application of these methods to monthly industrial production index

seasonaity can be defined as a pattern of a time series, which repeats at regular intervals each year. the seasonal adjustment of a time series refers to the isolation of both seasonal fluctations and also the basic trends of observed series. the de-seasonalised data, providing more redily interpretable measures of changes occurring in a given period, provides a chance to make a more realistic interpretation in economic sense. it is an undeniable fact that choice of seasonal effect in a series. in this thesis, the performance of most commonly used seasonal adjustment methods namely; X-12-ARIMA and TRAMO/SEATS on the monthly industrial production index has been analysed. the two methods are applied to the monthly industrial production index series and the results have been compared using specific criteria.