Forecasting for planning: Time series analysis

Planning is concerned primarily with developing strategies that will achieve a desired future. Accordingly, planners frequently prefer to give relatively little attention to recent trends and patterns and therefore to avoid the use of trend projections, time‐series‐analysis techniques, and other such methods. These planners maintain that their objective is to create an environment that will enable them to deviate from historical trends and therefore that history has little value. However, there are several ways in which statistical projections are useful to planners. In this article we will describe some of the more commonly used time‐series techniques and how they can be applied.