Average Turnaround time for maintenance dashboard

[hhajjali]

Hi,

I am creating a maintenance dashboard and I am trying to calculate the turnaround time of first delivery.

I have 2 tables:

Request: Key, Escalation Date, Closed Date, Status

Transactions: StatusFrom, StatusTo, TransactionDate

Status can be as follow: To Do, In Progress, In Quality Assurance, User Acceptance, Closed

A request can do some time ping pong between “In Quality Assurance” and “user Acceptance” if the answer was not satisfactory to the client.

I have a TAT (turnaround time) which I define as follow: The time between escalation date and the first time status is set to “User Acceptance”.

The TAT for each request is as follow: (Min({<StatusTo = {'User Acceptance'}>} TransactionDate) - [Escalation Date])

My challenge is that I need to calculate the average TAT, not all my request did reach the User acceptance phase, when I am using the following formula the KPI is not well calculated it give me ‘-‘ as results, can you help?

(Min({<toString = {'User Acceptance'}>} ChangeLogDate) - [Escalation Date])/Count({<toString = {'User Acceptance'}>} Key)

Thanks in advance.