The principle of parity in sentencing does not preclude disparity in results

R. v. Cox, 2011 ONCA 58, released today, has a useful discussion of parity :

[45] The principle of parity mandates that a sentence should be similar to sentences imposed on similar offenders for similar offences committed in similar circumstances: Criminal Code, s. 718.2(b). However, sentencing is an individualized process that by its very nature means that sentences imposed for offences of the same type will not always be identical. The principle of parity does not preclude disparity, where warranted by the circumstances, because of the principle of proportionality: R. v. L.M., at para. 36.

[46] This court will only interfere with the sentence imposed by a trial judge where the sentence is one that demonstrates a substantial and marked departure from sentences customarily imposed for similar offenders committing similar crimes. As this court has held, the principle of parity “does not require equal sentences, but only understandable sentences when examined together”: R. v. Issa, [1992] O.J. No. 1631 (Ont. C.A.) at paras. 8-12.

[47] Parity is only one of a number of important sentencing principles, including deterrence and denunciation, and the principle that a sentence must be proportionate to the gravity of the offence and degree of responsibility of the offender.