Troubleshooting Forecasting
This topic discusses some issues that may arise as you use forecasting in Tableau.
Null Forecasts
A null forecast results when you are using forecasting and modify the view in a manner that is incompatible with forecasting. The most obvious indication that you have a null forecast is that no forecast data is displayed in your view and the text No Forecast is displayed. Hover the cursor over this message to see why Tableau is unable to create a forecast:
Another indication is that the Forecast Indicator field on the Marks card shows Actual values, but no Estimate values:
To diagnose a null forecast, open the Describe Forecast dialog box from the Analysis menu (Analysis > Forecast > Describe Forecast) to see the error message. Then see Resolving Forecasting Errors for a suggested resolution.
Tableau also displays the error message in the Forecast Options dialog box (Analysis > Forecast > Forecast Options).
Because a forecast cannot be computed for a time series with null date values in the middle, actions that filter data, either explicitly or implicitly can trigger a null forecast. The Keep Only and Exclude commands on tooltips are examples of actions that can filter data implicitly—in some cases, these commands are removed when a forecast is shown. For example, if you have a time series of sales for each quarter from 2008 until 2012 and you exclude the Sales value for the second quarter of 2010, you will get a Null forecast because the time series is irregular. If, instead, you exclude the first quarter of 2008, you have shortened the time series but it remains regular. So, a valid forecast is still possible.