ABSTRACT
In this chapter we shall study methods of analyzing data over time. Researchers and managers alike are interested in planning for future changes. A first step in any analysis requires gathering the data. As a forecaster you must always keep in mind that, unless you have gathered the data for a specific purpose, you would have to examine the data carefully to determine its source and the circumstances under which they were gathered. Depending on the nature and operationalization of the data, you would have to be cautious in their use. For example, the monthly unemployment data gathered by certain government agencies may not show any changes in the unemployment rate because of how they have defined unemployment. In some cases a person must be laid off a number of weeks before they can be counted as unemployed.
