I have been trying to advise a business client recently who were recruiting an IT Projects Manager and were willing to look at both contractors and permanent staff but when they were calculating the contractor rate they were taking the permanent rate and dividing by 260 working days.
I tried to explain that this was not right and that when the contractor assessed their rates they would probably divide by 220 (taking account of holidays, non-working days, etc) then add in a percentage which in permanent parlance is the cost to employ - and that as a result their figure would be too low and they wouldn't get the skills or experience they wanted.
In essence, they agreed with me but my calculations were only based on personal experience rather than a specific comparator. Does anyone know where I can get a more scientific comparison eg a web-site ?