Project Task assessment calculation problem

To achieve this in DAX, you can create a calculated column for ActualDelay. Here's how you can do it:

First, you need to determine if the task's actual start time is delayed due to its predecessor. If the task's actual start time is greater than its planned start time and the predecessor's actual finish time is greater than the predecessor's planned finish time, then the task is delayed due to its predecessor.

Now, for the ActualDelay calculation:

If a task is delayed due to its predecessor, set ActualDelay to 0. Otherwise, calculate the delay as the difference between the actual finish time and the planned finish time.

Here's the DAX formula for the ActualDelay column:

ActualDelay =
VAR CurrentTaskID = Tasks[TaskID]
VAR PredecessorID = Tasks[Predecessor]
VAR PredecessorActualFinish = LOOKUPVALUE(Tasks[ActualFinish], Tasks[TaskID], PredecessorID)
VAR PredecessorPlanFinish = LOOKUPVALUE(Tasks[PlanFinish], Tasks[TaskID], PredecessorID)

RETURN
IF(
AND(
Tasks[ActualStart] > Tasks[PlanedStart],
PredecessorActualFinish > PredecessorPlanFinish
),
0,
Tasks[ActualFinish] - Tasks[PlanFinish]
)
In this formula, we're using the LOOKUPVALUE function to get the actual and planned finish times of the predecessor task. We then determine if the current task is delayed due to its predecessor. If it is, we set ActualDelay to 0. Otherwise, we calculate the delay as the difference between the actual and planned finish times.

I hope this helps! Let me know if you have any questions or need further clarification.