Forecasting is about predicting the future value of a measure. There are many mathematical models for forecasting. Tableau uses the model known as exponential smoothing. In exponential smoothing, recent observations are given relatively more weight than older observations. These models capture the evolving trend or seasonality of the data and extrapolate them into the future. The result of a forecast can also become a field in the visualization created.
Tableau takes a time dimension and a measure field to create a forecast.
Using the Sample-superstore, forecast the value of the measure sales for next year. To achieve this objective, following are the steps.
Step 1 − Create a line chart with Order Date (Year) in the columns shelf and Sales in the Rows shelf. Go to the Analysis tab as shown in the following screenshot and click Forecast under Model category.
Step 2 − On completing the above step, you will find the option to set various options for forecast. Choose the Forecast Length as 2 years and leave the Forecast Model to Automatic as shown in the following screenshot.
Click OK, and you will get the final forecast result as shown in the following screenshot.
You can also get minute details of the forecast model by choosing the option Describe Forecast. To get this option, right-click on Forecast diagram as shown in the following screenshot.