IF/INDEX function returning #INVALID DATA TYPE

connormaloney

In my function below i am trying to fill the actual start date column with a new date if the predecessor task's duration was extended. ive replaced the Predecessors@row with a number value and the formula returned actual dates, so i suspect this is where i incorrectly identify a row number in the index function. i also understand that this formula cant work for the first row and rows without predecessors. any help would be appreciated!

projectplannerex.jpg

=IF(INDEX($Predecessors$1:$[Actual Duration (days)]$31, Predecessors@row, 6) = INDEX($Predecessors$1:$[Actual Duration (days)]$31, Predecessors@row, 9), [Initial Start Date]@row, (INDEX($Predecessors$1:$[Actual Duration (days)]$31, Predecessors@row, 7)) + (INDEX($Predecessors$1:$[Actual Duration (days)]$31, Predecessors@row, 9)))

Lucas Rayala

@connormaloney -- Invalid Data Type is often triggered around dates when the wrong column type is selected (i.e. you are importing a date into a non-date column, or most-often you are trying to display non-date information in a date column).

Check to ensure that each column is a Date column (in the column properties). If everything seems correct, troubleshoot by testing your formula in parts. First, does the criteria in the if statement work (use a non-date column to check). Then check the date inputs to ensure they work as well.