The important reasons for the study of time series are as follows:
- The changes occuring in the values of the variable quantity of the time series indicate the situation that prevailed in the past and this knowledge becomes helpful in making decisions for the future.
- We can predict the future value or values of the variable quantity on the basis of the study of the time series.
- The policy decisions made on the basis of the study of time series, enable business firms, industrial houses and government organisations to formulate their development plans for future.
- The study of time series enable business firms, industrial houses and government organisation to compare their present performance of the economic activities with the past and make an assessment of the actual progress achieved. For example, the government can assess the changes occurred in the inflation rate on the basis of wholesale price index numbers during the five year plan period.
