Teaching decomposition forecasting models using an Excel-based spreadsheet application with Solver and randomisation

This article describes an Excel-based application to help teach forecasting with additive and multiplicative decomposition models using the standard Solver add-in to identify intercept, linear trend, and seasonality parameters. By using the application, students can see how easy it is to apply Solver's GRG nonlinear solving method in a relatively familiar forecasting context. To give additional opportunities to practice and encourage academic integrity, the software randomly generates data and layouts and disables copying and pasting between windows. Homework results suggest it provides a challenge despite offering extensive feedback and help. Students reported that it helped them learn forecasting and Excel. Those who correctly completed the assignment have had mixed results on a variety of forecasting exam questions. Even when using innovative technologies such as this application, additional resources, motivation, and opportunities may be necessary to facilitate breadth and depth of learning beyond the essentials required to complete assignments.