Calculated field to show difference between Created and when certain field changed

Question

I'm not sure if this is possible, but I'll ask anyway.

We have items that have a field called "Status", and we'd like metrics (which is where the calculated field comes in) for how long (in days) was it between when the item was created and when "Status" went to "Approved" for the approved items. It may get modified after this, so I can't just assume it is the "Last Modified", though I may have to and then just use that with the grain of salt.

So can the calculated field be used to look at when the field went to "Approved" and return that date, and then do the calculation? Or am I stuck with DATEDIF([Created], [Last Modified], "d").

I've reviewed the MSDN documentation on Calculated Fields, here: http://msdn.microsoft.com/en-us/library/bb862071(v=office.12).aspx

Thanks in advance.

Answer 1

I think you'd need to do it with a workflow/event receiver to check the status field and set an approved date field when the item changes. Then you'd calculate off of created and the approved date to get your metric.

Using modified like you said isn't going to be reliable.