Spiegelhalter David J
MRC Biostatistics Unit, Institute of Public Health, Cambridge CB2 2SR.
BMJ. 2005 Oct 29;331(7523):1013-5. doi: 10.1136/bmj.331.7523.1013.
Chance variability makes it impossible to assess reliably whether individual trusts are meeting annual targets for reduction in the risk of MRSA infection