Returns or sets the item in the base field for a custom calculation. Valid only for data fields. Read/write Variant.
Remarks
This property is not available for OLAP data sources.
Example
This example sets the data field in the PivotTable report on Sheet1 to calculate the difference from the base field, sets the base field to the field named "ORDER_DATE," and then sets the base item to the item named "5/16/89."
With Worksheets("Sheet1").Range("A3").PivotField
.Calculation = xlDifferenceFrom
.BaseField = "ORDER_DATE"
.BaseItem = "5/16/89"
End With