The article for Refugee Survey Quarterly endeavours to use the legal principle of proportionality as a tool to critique immigration detention practices and policies. To this end, the article proposes a methodology for assessing operations at detention centres that opens the phenomenon up to empirical study and allows for comparative research of detention practices across a multiplicity of cases. It then highlights a discrete set of dimensions that can be used to measure the degree to which states’ employment of detention is proportional to the limited ends established in law for this type of deprivation of liberty. The article can be accessed here.