Optimisation can be stated as '..a process or method used to make a system of protection as effective as possible within the given criteria and constraints..'. With respect to Radiation Protection, the ICRP 103 publication states '.consider how best to use resources in reducing radiation risks to individuals and populations ... so far as is reasonably achievable, social and economic factors being taken into account'. This is the basis of the ALARA principle, and the UK ALARP principle (but ALARP does not consider social and economic factors and is developed from Case Law)). Radiation protection uses optimisation to reduce exposures below Dose Limits.