There has been a rapid development of measurement systems in the health services in the United Kingdom (UK) over recent years, not always matched by a thorough understanding of the phenomenon being measured and rarely based on any assessment of reliability or validity A particularly flagrant example of this process is the development of nursing workload measurement systems (NWMS) The estimates from four NWMS were examined They were substantially different from each other for no obvious reason, and the difference between any of the estimates and the actual nursing hours worked could not be explained in terms of any other aspect of the nursing process There is no evidence that the NWMS deployed in the UK are anything more than an expensive numbers game, without this kind of investigation of how they actually work in practice, it would be prudent to be wary about any of the measurement systems which have been proposed Yet many of the measurement systems used in other sectors of the health service are equally untested