To follow this recipe, open B05527_06 – STARTER.twbx. Use the worksheet called Forecasting and connect to the MasterTable (FlooddataMasterListrev) data source:

Here are the steps to create the view in this recipe:

Tableau's forecasting feature uses a technique called exponential smoothing, as described in the online documentation at http://bit.ly/tableau-forecasting. Typically, when forecasting, one of the axes needs to be temporal (or date-related).

To add a forecast, we simply need to right-click on the view and, under Forecast, select Show Forecast. Alternatively, this can be added from the Analysis menu.

To describe the forecast, we can also right-click on the view, and under Forecast, select Describe Forecast. The window that pops up has two panes: one for Summary and another for Models. Here is an example of the Summary window for a forecast:

The Forecast Model provides additional information on the model used, including the model trend, seasonality, quality metrics, and smoothing coefficients:

There are not many options to change or set in Tableau's forecasting functionality. The limited options that can be changed include the forecast length, seasonality, and prediction intervals:

Additional forecast results, as shown in the following screenshot, are made available through the measure in the Rows or Columns shelf that is being forecasted:

If you want to use more complex models for your forecast, you can take advantage of R integration with Tableau.

Please refer to the Performing linear regression with R recipe in this chapter