Mark Stafford and Mark Warr's reconceptualization of deterrence theory was first published in 1993. Their theory challenged the distinctions between specific and general deterrence and maintain that the same people are often subject to both specific and general deterrence. Stafford and Warr's theory of reconceptualization of deterrence is most compatible with the 18th century theories of Beccaria and Bentham. Both Beccaria and Bentham were philosophers concerned with legal and penal reform and challenged many of the distinctions of deterrence or punishment.