I manage a team of data entry staff, who are given tasks to complete. This isn't micro managed, at all - each person has their own repeated tasks on a weekly or a monthly basis, one of the team has been with the business for around 9 years. She's always been very slow at the data entry but is meticulous and never makes a mistake,
Over the last 12 months she's really slowed down, we've lost some of the tasks she had over the past 2 years, which should have free'd up some of her time yet she is still 'busy' all day every day when I'm passing new tasks to her - I'm now going to have to go down a performance management route as it just isn't sustainable for the rest of the team to be working at twice the rate (and also not making regular mistakes)
My question is, as a manager (of around 5 years, first team I've managed is here after working my way up) I've not had to go down this route officially past a coupe of informal chats before, what would you use as the benchmark? Should I be doing the tasks she's being given to get an idea of a time for them to take, I've made a note of what I expect the tasks should take (with an added 10% allowance) and in the last 3 months its become apparent that I cant work out where around 10 hours a week of her time are being spent.