I use the report function. Under the row category select assigned tech. Add a report filter for the status values you consider closed. We have Closed and Installed. There are two selections for row category related to techs. Orginal Tech and Assigned Tech. If the ticket is closed, then the Assigned Tech was the last one on that ticket.
Thanks for that, I'll give it a go but I have a recollection that the assigned tech doesnt always match with the person that changed the status to closed.