The main problems in the use of productivity levels are to do with measurement.
First, the output of organisations is heterogeneous and therefore has to be measured in
monetary terms. But some outputs are transferred within or between firms without a
price being attached to them; also, many of the outputs of the public sector are not
priced. There are two main inputs into the production process and these too are subject
to measurement difficulties. As far as labour is concerned, a common measure of productivity
is output per person employed (see Figure 8.8), but this does not take into