At para. 24, the Appeals Chamber recalled its finding in the Janković case:

Nothing in Rule 11bis of the Rules indicates that [a] Referral Bench is obliged to consider the gravity of the crimes charged and the level of responsibility of accused in other cases in order to make its referral decision. Although the Referral Bench may be guided by a comparison with an indictment in another case, it does not commit an error of law if it bases its decision on referral merely on the individual circumstances of the case before it.[1]

348. The Appeals Chamber has held that sentences of like individuals in like cases should be comparable.[1]While similar cases do not provide a legally binding tariff of sentences, they can be of assistance in sentencing if they involve the commission of the same offences in substantially similar circumstances.[2] The relevance of previous sentences is however often limited as a number of elements, relating, inter alia, to the number, type and gravity of the crimes committed, the personal circumstances of the convicted person and the presence of mitigating and aggravating circumstances, dictate different results in different cases such that it is frequently impossible to transpose the sentence in one case mutatis mutandis to another.[3] This follows from the principle that the determination of the sentence involves the individualisation of the sentence so as to appropriately reflect the particular facts of the case and the circumstances of the convicted person.[4]

349. As a result, previous sentencing practice is but one factor among a host of others which must be taken into account when determining the sentence. Nonetheless, as held by the Appeals Chamber in Jelisić, a disparity between an impugned sentence and another sentence rendered in a like case can constitute an error if the former is out of reasonable proportion with the latter. This disparity is not in itself erroneous, but rather gives rise to an inference that the Trial Chamber must have failed to exercise its discretion properly in applying the law on sentencing:

The Appeals Chamber agrees that a sentence should not be capricious or excessive, and that, in principle, it may be thought to be capricious or excessive if it is out of reasonable proportion with a line of sentences passed in similar circumstances for the same offences. Where there is such disparity, the Appeals Chamber may infer that there was disregard of the standard criteria by which sentence should be assessed, as prescribed by the Statute and set out in the Rules. But it is difficult and unhelpful to lay down a hard and fast rule on the point; there are a number of variable factors to be considered in each case.[6]

In considering whether the Trial Chamber should have given more weight to the sentence imposed on an accused who pleaded guilty to his involvement in the same criminal scheme, the Appeals Chamber held:

57. […] [W]hile sentences of like individuals in like cases should indeed be comparable,[1] trial chambers have broad discretion in determining the appropriate sentence on account of their obligation to tailor the penalties to fit the individual circumstances of the convicted person and to reflect the gravity of the crimes.[2] Comparison between cases is thus generally of limited assistance.[3]

362. […] [A] review of the ICTR’s case law finds that those who, like the Appellant, have been convicted of genocide as a principal perpetrator have frequently been sentenced to life imprisonment.[1] In any case, the Trial Chamber is not bound by previous sentencing practices. […]

32. As previously noted in the Dragan Nikolić case, the precedential effect of previous sentences rendered by the International Tribunal and the ICTR is not only “very limited”[1] but “also not necessarily a proper avenue to challenge a Trial Chamber’s finding in exercising its discretion to impose a sentence”.[2] The reasons for this are clearly set out in the case law of the International Tribunal: (1) such comparison can only be undertaken where the offences are the same and committed in substantially similar circumstances;[3] and (2) a Trial Chamber has an overriding obligation to tailor a penalty to fit the individual circumstances of the accused and the gravity of the crime.[4]

33. In the Jelisić case, in addressing the appellant’s arguments to the effect that he was given a sentence in excess of those rendered in other cases, the Appeals Chamber held the following:

The Appeals Chamber agrees that a sentence should not be capricious or excessive, and that, in principle, it may be thought to be capricious or excessive if it is out of reasonable proportion with a line of sentences passed in similar circumstances for the same offences.  Where there is such disparity, the Appeals Chamber may infer that there was disregard of the standard criteria by which sentence should be assessed, as prescribed by the Statute and set out in the Rules.[5]

In the present case, the Appellant is not alleging that his case falls within a pattern or a line of sentences passed in similar circumstances for the same offences. He only refers to one case which in his view bears some similarities with his own. The finding of the Appeals Chamber in Jelisić was concerned with a comparison with a “line of sentences” and not with a comparison with one single case. Furthermore, the Appeals Chamber emphasises that, as a general principle, comparisons with other cases as an attempt to persuade the Appeals Chamber to either increase or reduce the sentence are of limited assistance: the differences are often more significant than the similarities and the mitigating and aggravating factors dictate different results.[6] In this case, even assuming that the two cases were so similar as to be meaningfully comparable, the Appellant’s sentence is not so out of reasonable proportion with Plavšić’s sentence so as to suggest capriciousness or excessiveness. The Appeals Chamber will therefore not engage in a comparison between these two cases. In light of the foregoing, this part of the Appellant's second ground of appeal is dismissed.

721. [W]hile the Appeals Chamber does not discount the assistance that may be drawn from previous decisions rendered, it also concludes that this may be limited.  On the other hand, it reiterates that, in determination of sentence, “due regard must be given to the relevant provisions in the Statute and the Rules which govern sentencing, as well as the relevant jurisprudence of this Tribunal and the ICTR, and of course to the circumstances of each case.”[1]

See also paragraphs 719-720.

756. Public confidence in the integrity of the administration of criminal justice (whether international or domestic) is a matter of abiding importance to the survival of the institutions which are responsible for that administration.  One of the fundamental elements in any rational  and fair system of criminal justice is consistency in punishment.  This is an important reflection of the notion of equal justice.  The experience of many domestic jurisdictions over the years has been that such public confidence may be eroded if these institutions give an appearance of injustice by permitting substantial inconsistencies in the punishment of different offenders, where the circumstances of the different offences and of the offenders being punished are sufficiently similar that the punishments imposed would, in justice, be expected to be also generally similar.

757. This is not to suggest that a Trial Chamber is bound to impose the same sentence in the one case as that imposed in another case simply because the circumstances between the two cases are similar.  As the number of sentences imposed by the Tribunal increase, there will eventually appear a range or pattern of sentences imposed in relation to persons where their circumstances and the circumstances of their offences are generally similar.  When such a range or pattern has appeared, a Trial Chamber would be obliged to consider that range or pattern of sentences, without being bound by it, in order only to ensure that the sentence it imposes does not produce an unjustified disparity which may erode public confidence in the integrity of the Tribunal’s administration of criminal justice.

758.    At the present time, there does not exist such a range or pattern of sentences imposed by the Tribunal.  The offences which the Tribunal tries are of such a nature that there is little assistance to be gained from sentencing patterns in relation to often fundamentally different offences in domestic jurisdictions, beyond that which the Tribunal gains from the courts of the former Yugoslavia in accordance with Article 24 of the Tribunal’s Statute.  At the present time, therefore, in order to avoid any unjustified disparity, it is possible for the Tribunal to have regard only to those sentences which have been imposed by it in generally similar circumstances as to both the offences and the offenders.  It nevertheless must do so with considerable caution.  As the Appeals Chamber discusses further below[2] comparisons with sentences imposed in other cases will be of little assistance unless the circumstances of the cases are substantially similar.  However, in cases involving similar factual circumstances and similar convictions, particularly where the sentences imposed in those other cases have been the subject of consideration in the Appeals Chamber, there should be no substantial disparity in sentence unless justified by the circumstances of particular accused.

See also paragraph 798.

326. Regarding the comparison with the sentence imposed on Galić on appeal, the Appeals Chamber recalls that “sentences of like individuals in like cases should be comparable”.[1] However, similar cases do not provide “a legally binding tariff of sentences”.[2] While the Appeals Chamber does not discount the assistance that may be drawn from previous decisions, such assistance is often limited, as each case contains a multitude of variables.[3] Differences between cases are often more significant than similarities and different mitigating and aggravating circumstances might dictate different results.[4]

681. Sentences of like individuals in like cases should be comparable and, in this regard, the Appeals Chamber “does not discount the assistance that may be drawn from previous decisions rendered”.[1] Indeed, the Appeals Chamber has observed that a sentence may be considered “capricious or excessive if it is out of reasonable proportion with a line of sentences passed in similar circumstances for the same offences”.[2] The underlying question is whether the particular offences, the circumstances in which they were committed, and the individuals concerned can truly be considered “like”. Any given case contains a multitude of variables, ranging from the number and type of crimes committed to the personal circumstances of the individual. Often, too many variables exist to be able to transpose the sentence in one case mutatis mutandis to another. Hence the Appeals Chamber has previously stated that:

While it does not disagree with a contention that it is to be expected that two accused convicted of similar crimes in similar circumstances should not in practice receive very different sentences, often the differences are more significant that the similarities, and the mitigating and aggravating factors dictate different results.[3]

Thus, while comparison with other sentences may be of assistance, such assistance is often limited.[4] For these reasons, previous sentences imposed by the Tribunal and the ICTR are but one factor to be taken into account when determining the sentence.[5]

238. Finally, the Appeals Chamber is not persuaded by the Prosecution’s reading of the Gacumbitsi Appeal Judgement and its relevance to this case. Just as there is no category of cases within the jurisdiction of the Tribunal where the imposition of a sentence of life imprisonment is per se barred, there is also no category of cases where it is per se mandated. Each case remains to be examined on its own individual facts.[1]

766. The Appeals Chamber understands that the Prosecution does not challenge the Trial Chamber’s factual determinations regarding the gravity of crimes, but rather contends that the sentence it imposed on Karadžić was “manifestly inadequate” and unreasonable given the “unprecedented gravity” of his crimes.[1] Taking into account the Trial Chamber’s conclusions reflecting the magnitude of Karadžić’s crimes, the Appeals Chamber is in agreement with the Prosecution’s position. While fully cognizant of the Trial Chamber’s discretion in sentencing, the Appeals Chamber considers that the 40-year sentence inadequately reflects the extraordinary gravity of Karadžić’s crimes as well as his central and instrumental participation in four joint criminal enterprises, which spanned more than four years and covered a large number of municipalities in Bosnia and Herzegovina.

767. The incongruence between the gravity of Karadžić’s crimes and his 40-year sentence is apparent when Karadžić’s crimes and punishment are compared to the life sentences imposed on Tolimir, Beara, Popović, and Galić for their responsibility in only a fraction of Karadžić’s crimes. The Appeals Chamber notes that the Trial Chamber did not explicitly consider these cases in its determination of Karadžić’s sentence.[2] The Appeals Chamber recalls that trial chambers are under no obligation to expressly compare the case of one accused to that of another.[3] Moreover, it is settled jurisprudence that any given case may contain a multitude of variables, ranging from the number and type of crimes committed to the personal circumstances of the individual.[4] However, a “disparity between sentences rendered in similar cases may be considered ‘capricious or excessive’, hence warranting the intervention of the Appeals Chamber, ‘if it is out of reasonable proportion with a line of sentences passed in similar circumstances for the same offences’”.[5]

See also paras. 768 to 771.

[…]

772. In the present case, the Appeals Chamber observes the Trial Chamber’s findings that Galić was a named member of the Sarajevo JCE,[6] and that Tolimir,[7] Beara,[8] and Popović[9] either supported or were named members of the Srebrenica JCE. Additionally, as noted above, these individuals were high‑ranking members of the VRS or the SRK, which were under Karadžić’s “authority” as the President of Republika Srpska and Supreme Commander of its forces.[10] The fact that Tolimir, Beara, Popović, and Galić were each sentenced to life imprisonment for participating in only one of the four joint criminal enterprises involved in this case, and the fact that they were subordinated to Karadžić, further demonstrates that the 40-year sentence imposed on Karadžić was inadequate.

773. Given the above, the Appeals Chamber considers that the sentence of 40 years imposed on Karadžić by the Trial Chamber underestimates the extraordinary gravity of Karadžić’s responsibility and his integral participation in “the most egregious of crimes” that were committed throughout the entire period of the conflict in Bosnia and Herzegovina and were noted for their “sheer scale” and “systematic cruelty”.[11] In the circumstances of this case, the sentence the Trial Chamber imposed was so unreasonable and plainly unjust that the Appeals Chamber can only infer that the Trial Chamber failed to properly exercise its discretion.

774. The Appeals Chamber finds, Judges de Prada and Rosa dissenting, that the Trial Chamber committed a discernible error and abused its discretion in imposing a sentence of only 40 years of imprisonment. The Appeals Chamber, Judges de Prada and Rosa dissenting, therefore grants Ground 4 of the Prosecution’s appeal.[12] The impact of this finding is addressed below.

[…]

776. […] In light of Karadžić’s position at the apex of power in Republika Srpska and its military, his instrumental and integral participation in the four joint criminal enterprises, the scale and systematic cruelty of the crimes committed, the large number of victims, the continued impact of these crimes on victims who have survived, as well as the relevant mitigating and aggravating factors, the Appeals Chamber, Judges de Prada and Rosa dissenting, finds that the only appropriate sentence in the circumstances of this case is imprisonment for the remainder of Karadžić’s life.

See also para. 777.