You have been asked to plan the labour force for a job of work that will require the equivalent of five skilled workers for a period of 30 days. Within that period there is an expectation of 25 days of productive work and five days equivalent of non-productive work relating to rest periods and statutory holiday leave. You have only been able to find three workers of sufficient skill who will work full-time. There are two part-timers who together will cover the equivalent of one further full-time worker. You will need to hire agency staff on an hourly basis to make up the shortfall.

Explain the problems you will face in estimating the labour cost of the job.