Show predicted values using a dashed border
Many times, during sales forecasting or project planning, you need to show predicted values on the chart. To make sure the user doesn’t mix up the known and the predicted values when he is deep in his analysis, it is best to show predicted values using a dashed border, as shown in the following screenshot:
Dashed borders are often used to highlight a data set as well, but with a small note in the subcaption, you can be sure to eliminate the confusion.