The parity principle is an aspect of the systemic objectives of consistency and equality before the law – the treatment of like cases alike, and different cases differently: Green v The Queen (2011) 244 CLR 462 at . The avoidance of unjustifiable disparity between the sentences imposed upon offenders involved in the same criminal conduct or a common criminal enterprise is a matter that is “required or permitted to be taken into account by the court” under s 21A(1): Green v The Queen at . The principle is applied at first instance and on appeal (see below). An assertion by an offender of unjustified disparity can be a separate ground of appeal: Green v The Queen at .
Sentencing courts, prosecutorial bodies and defence counsel should take steps to ensure related offenders are sentenced by the same sentencing judge, preferably at the same time: Dwayhi v R (2011) 205 A Crim R 274 at –. As a matter of practice, it is in the highest degree desirable that co-offenders be sentenced by one judge: Postiglione v The Queen (1997) 189 CLR 295. The desirability of this practice has been repeatedly emphasised on the basis that it serves the public interest in consistent and transparent sentencing of related offenders: Dwayhi v R at –, ; see also R v Nguyen (2010) 205 A Crim R 106 at , ; Ng v R  NSWCCA 227 at –. Many of the parity problems that arise on appeal could be avoided if co-offenders were sentenced at the same time by the same judge.
If co-offenders are not sentenced by the same judge, questions will arise as to whether the second judge is bound by the findings of fact made by the first judge. In Baquiran v R  NSWCCA 221, the court held that although the parity principle applies, the second judge was not bound by findings made by another judge in different sentencing proceedings.
[10-805] A justifiable sense of grievance
The decision of Lowe v The Queen (1984) 154 CLR 606 is cited as the principal source of the parity principle. Dawson J, with whom Wilson J agreed, summarised the parity principle as follows at 623:
There is no rule of law which requires co-offenders to be given the same sentence for the same offence even if no distinction can be drawn between them. Obviously where the circumstances of each offender or his involvement in the offence are different then different sentences may be called for but justice should be even-handed and it has come to be recognised both here and in England that any difference between the sentences imposed upon co-offenders for the same offence ought not to be such as to give rise to a justifiable sense of a grievance on the part of the offender with the heavier sentence or to give the appearance that justice has not been done.
See also Gibbs CJ at 609, Brennan J at 617 and Mason J at 610. There is also an exposition of the principle by Dawson and Gaudron JJ in Postiglione v The Queen (1997) 189 CLR 295 at 301. In Green v The Queen (2011) 244 CLR 462, the High Court considered the application of the parity principle in sentence appeals (see further below).
Inconsistency in the sentencing of co-offenders gives rise to a justifiable sense of grievance. Thus, in Lowe v The Queen (1984) 154 CLR 606, Mason J at 610 (as he then was) said:
Just as consistency in punishment — a reflection of the notion of equal justice — is a fundamental element in any rational and fair system of criminal justice, so inconsistency in punishment, because it is regarded as a badge of unfairness and unequal treatment under the law, is calculated to lead to an erosion of public confidence in the integrity of the administration of justice. It is for this reason that the avoidance and elimination of unjustifiable discrepancy in sentencing is a matter of abiding importance to the administration of justice and to the community.
[10-810] Co-offenders convicted of different charges
Formal identity of charges against the offenders whose sentences are compared is not a necessary condition of the application of the principle of parity: Green v The Queen (2011) 244 CLR 462 at . Put simply, the parity principle is not confined to sentences imposed upon co-offenders who have committed the same crime; it can also be applied to sentences imposed upon persons who are co-offenders by virtue of having been engaged in the same criminal enterprise, regardless of the charges that have been actually laid against them: Green v The Queen at ; Jimmy v R (2010) 77 NSWLR 540 at , . The High Court held in Green v The Queen that the Court of Criminal Appeal had erred by discounting the sentence imposed upon Taylor who was convicted of a lesser offence “as a comparator of any significance”: Green v The Queen at .
The High Court acknowledged the statement in Jimmy v R, of Campbell JA at  which sets out “some of the limits” of the principle of parity. Howie J at  and Rothman J at  agreed. Campbell JA said at  [case references excluded]:
There are significant limitations, however, on reducing a sentence on the basis of that of a co-offender who has committed a different crime. At least some of the limits on the use of the parity principle in such a case are:
It cannot overcome those differences in sentence that arise from a prosecutorial decision about whether to charge a person at all, or with what crime to charge them … [In this regard, R v Kerr  NSWCCA 234 should no longer be followed: , , per Campbell JA;  per Howie J,  per Rothman J.]
If it is used to compare the sentences of participants in the same criminal enterprise who have been charged with different crimes, there can be significant practical difficulties. Those practical difficulties become greater the greater the difference between the crimes charged becomes, and can become so great that in the circumstances of a particular case a judge cannot apply it, or cannot see that there is any justifiable sense of grievance arising from the discrepancy …
It cannot overcome differences in sentence that arise from one of the co-offenders having been given a sentence that is unjustifiably low …
There are particular difficulties in an applicant succeeding in a disparity argument where the disparity is said to arise by comparison with the sentence imposed on a co-offender who has been charged with an offence that is less serious than that of the applicant … However Nguyen stands as one example where that result arose.
The majority in Green v The Queen added at :
The greater the difference between the crimes, the greater the practical difficulties, particularly where disparity is said to arise out of a sentence imposed on a co-offender who has been charged with an offence that is less serious than that of the appellant. The existence of those difficulties may be accepted.
In Gaggioli v R  NSWCCA 246, a co-offender pleaded guilty to a lesser charge with a lower maximum penalty. The court held that prosecutorial discretion is unreviewable and there could be no justifiable sense of grievance caused by the different approach taken by the prosecution regarding the two offenders.
In Dunn v R  NSWCCA 108, the parity principle did not apply where the offender was sentenced for an offence but his co-offenders had the same offence taken into account on a Form 1. No relevant comparison can be made between a sentence imposed for an offence and an unspecified increase in a sentence resulting from the charge being taken into account on a Form 1: Dunn v R at .
The application of the parity principle can depend on findings of facts about the role of individual offenders in a crime. It is often appropriate to differentiate between the relative culpability amongst co-offenders by reference to the conduct of each in the joint criminal enterprise: R v JW (2010) 77 NSWLR 7. However, there are limits to which this can occur with respect to the objective seriousness of the offence, because of the existence of the common purpose to commit the offence: R v Wright  NSWCCA 3 applied. And in assigning roles to the specific participants, the sentencing judge should not lose sight of the fact that they were all participants in the crime: R v JW at  McClellan CJ at CL, Howie and Johnson JJ. Subjective features of individual offenders will result in differences — sometime significant — in the sentences imposed between offenders: R v JW at . However, there are always differences in the objective and subjective elements in cases involving multiple offenders. Consideration should be given to whether the sentence imposed on a co-offender is reasonably justified given those differences: Miles v R  NSWCCA 266 at .
See generally, A Dyer and H Donnelly, “Sentencing in complicity cases — Part 1: Joint criminal enterprise”, Sentencing Trends and Issues, No 38, Judicial Commission of NSW, 2009.
[10-820] Juvenile and adult co-offenders
Where one offender is sentenced in the Children’s Court and the other in an adult’s jurisdiction, it is proper for the court to recognise that the sentencing takes place in very different regimes: R v Ho (unrep, 28/2/97, NSWCCA). In R v Colgan  NSWCCA 292, Spigelman CJ, after referring to R v Govinden (1999) 106 A Crim R 314, held at  that, although parity considerations do not arise when comparing a person sentenced in the Children’s Court with adults:
… that does not mean that the sentence imposed on a person in the Children’s Court, which would otherwise give rise to issues of parity, is irrelevant. This is so for the reason that an individual sentenced as an adult may very well have a justifiable sense of grievance with respect to that very difference of the regimes.
In R v Wong  NSWCCA 247, Kirby J said at :
The principles relating to parity, where the comparison is with a young offender, have been gathered by Wood CJ at CL in R v Boney  NSWCCA 432. A number of propositions can be stated:
First, in fashioning a sentence for an adult involved in the same crime, it is relevant to have regard to a sentence imposed by the Children’s Court upon a co-offender.
Second, the worth of that comparison, however, will be limited given the different sentencing objectives and other considerations in the Children’s Court.
Third, in determining whether there is a justifiable sense of grievance, it must be recognised that a stage can be reached where the inadequacy of the sentence imposed upon a co-offender is such that any sense of grievance engendered by it cannot be regarded as legitimate (R v Diamond (NSW, CCA, 18.2.93, per Hunt CJ at CL).
Fourth, at an appellant level, where there is a justifiable sense of grievance in the adult offender, that does not oblige the court to intervene. It has a discretion to intervene. It should not intervene where to do so would produce a sentence which does not reflect the objective gravity of the crime.
See further Subjective factors commonly relevant to robbery at [20-300].
[10-830] Parity and totality
In Postiglione v The Queen (1997) 189 CLR 295, the High Court considered the relationship between the principles of parity and totality. Dawson and Gaudron JJ pointed out that disparity is not simply the imposition of different sentences for the same offence but a question of disproportion between them. Parity is a matter to be determined by having regard to the circumstances of the co-offenders and their respective degrees of culpability. Different criminal histories and custodial patterns may “justify a real difference in the time each will serve in prison” and “like must be compared with like” when applying the parity principle: at 878. Justice Kirby said that the parity and totality principles are in the nature of checks required out of recognition that the task of sentencing is not mechanical. The sentence may require adjustment because it is out of step with the parity principle or it may offend the totality principle because it is not “just and appropriate”, as in the case of a “crushing” sentence. Any adjustments to sentence, his Honour observed “involve subtle considerations which defy precision either of description or implementation”: at 901.
In the Court of Criminal Appeal decision consequent upon that case, Hunt CJ at CL said that the principle in Lowe v The Queen (1984) 154 CLR 606 remains unaffected by the High Court’s decision: R v Postiglione (1997) 98 A Crim R 134.
For the totality principle, see Application of totality principle at [8-210].
[10-840] Severity appeals and parity
The plurality in Green v The Queen (2011) 244 CLR 462 at – explained how the parity principle should be applied in severity appeals as follows:
The sense of grievance necessary to attract appellate intervention [in a severity appeal] with respect to disparate sentences is to be assessed by objective criteria. The application of the parity principle does not involve a judgment about the feelings of the person complaining of disparity. The court will refuse to intervene where disparity is justified by differences between co-offenders such as age, background, criminal history, general character and the part each has played in the relevant criminal conduct or enterprise.
A court of criminal appeal deciding an appeal against the severity of a sentence on the ground of unjustified disparity will have regard to the qualitative and discretionary judgments required of the primary judge in drawing distinctions between co-offenders. Where there is a marked disparity between sentences giving rise to the appearance of injustice, it is not a necessary condition of a court of criminal appeal’s discretion to intervene that the sentence under appeal is otherwise excessive.
The test for establishing disparity has been described as whether the asserted disparity is “gross, marked or glaring” (see such examples as Tan v R  NSWCCA 96 at  and Wan v R  NSWCCA 261 at ). However, in Cameron v R  NSWCCA 229 at –, Hamill J observed the use of that epithet did not reflect the test which is whether the principles of equal justice have been misapplied. That approach was endorsed in Miles v R  NSWCCA 266 at , –. Using such descriptors is intended to ensure the principle applies when the discrepancy in sentences is not reasonably explained by the degree of difference between co-offenders and their offending: Miles v R at ; Wan v R at ; DS v R  NSWCCA 267 at . The principle is not to be applied in an unduly technical way: Miles v R at ; Cameron v R at .
The discretion to reduce a sentence to a less than adequate level would not require an appellate court to reduce the sentence to a level which would be, as Street CJ put it in R v Draper (unrep, 12/12/86, NSWCCA), “an affront to the proper administration of justice”: Green v The Queen at .
[10-850] Crown appeals and parity
The application of the parity principle in Crown appeals is different than when it is applied in severity appeals: Green v The Queen (2011) 244 CLR 462 at –. The purpose of Crown Appeals — of laying down principles for the governance and guidance of courts — is a limiting principle: Green v The Queen at –. If disparity is apprehended the residual discretion to dismiss a Crown Appeal is enlivened. The High Court framed the approach as follows in Green v The Queen at :
… a powerful consideration against allowing a Crown appeal would be the resultant creation of unjustifiable disparity between any new sentence and an unchallenged sentence previously imposed upon a co-offender. The question would then arise: would the purpose of Crown appeals under s 5D be served by allowing the appeal? If the result of doing so would be a sentence “adequate” on its face, but infected by an anomalous disparity which is an artifact of the Crown’s selective invocation of the Court’s jurisdiction, the extent of the guidance afforded to lower courts may be questionable.
The High Court in Green v The Queen cited the following passage of Howie J in R v Borkowski (2009) 195 A Crim R 1 at  with approval:
… the purpose of a Crown appeal is not simply to increase an erroneous sentence imposed upon a particular individual. It has a wider purpose, being to achieve consistency in sentencing and the establishment of sentencing principles. That purpose can be achieved to a very significant extent by a statement of this Court that the sentences imposed upon the respondent were wrong and why they were wrong.
If the Court of Criminal Appeal concludes the inadequacy of the sentence appealed from is so marked that it amounts to “an affront to the administration of justice” which risks undermining public confidence in the criminal justice system, the court is justified in interfering with the sentence notwithstanding the resultant disparity with an unchallenged sentence imposed on a co-offender: Green v The Queen at  citing R v Harris (2007) 171 A Crim R 267 at , .
In Green v The Queen, the High Court held that the Court of Criminal Appeal erred in failing to give adequate weight “to the purpose of Crown appeals and the importance of the parity principle”: Green v The Queen at . The court also erred in taking into account its opinion that the sentence imposed upon a co-offender was manifestly inadequate. The sentence had not been raised by a Crown appeal and had not been the subject of argument by the parties at the hearing of the appeal: Green v The Queen at .