Revenue Per Employee is calculated by dividing your revenue, for the current period, by all your full time equivalent employees (which you entered when setting up the company and this number can be amended in the Advance tab of Settings). For clients that outsource, this will also include full time equivalent subcontractors.

If you select a finalised month (see red square above) that isn't the financial year end then the figures will be annualised for the current financial period.

The little coloured number in the lefthand corner is the amount difference in the revenue per employee between now and the previous financial year.