Sentencing is about the allocation of pain. This can be measured in the euro value of a fine, in hours of community service, or in months of imprisonment.

The discretion that judges enjoy allows them to tailor sentences to individual circumstances. This means that similar cases can result in widely divergent outcomes or that the sanction imposed in a particular case can seem unduly lenient (or harsh). Such variation is often viewed by a perplexed and angry public as springing from a combination of capriciousness and remoteness from community sentiment.

Although less structured than elsewhere, sentencing in Ireland is not devoid of guiding principles. The most important of these is that the punishment must be proportionate to the gravity of the offence and the personal circumstances of the offender. While this principle is easy to state, the balance entailed can be difficult to strike.

There are several steps to be taken in the selection of a proportionate sentence. First of all, it is necessary to weigh the harm done (or risked) in a particular case and the offender’s intent. How does the crime compare with others in the same category and how should this category be ranked in terms of seriousness? What degree of planning was involved?

Next, account is taken of the offender’s character. The appropriate weight to accord to previous convictions is a knotty problem. There are three main perspectives on this issue. First, that a criminal record is irrelevant and that first-time offenders and recidivists should receive the same penalty if they commit the same crime.

Personal culpability

A second school of thought holds that the existence of a record indicates a greater degree of personal culpability and this justifies an enhanced penalty.

The third approach is based on what is known as the principle of progressive loss of mitigation. This gives individuals the benefit of the doubt the first time they come into conflict with the law, but this tolerance wanes in the event of subsequent encounters. The logic here is that anyone can experience a temporary loss of self-control but a single lapse does not imply commitment to a criminal lifestyle.

Different judges will favour different approaches but the third is probably the most common. The absence of prior convictions will usually redound to the individual’s advantage.

Offenders who accept responsibility for the harm they have caused and spare the victim the trauma of a court appearance benefit from a discount on the sentence. The discount is larger if the guilty plea is entered at an early stage in the proceedings thereby saving the State the expense of preparing for a trial and the victim the pain and uncertainty of a protracted delay before matters are resolved.

If there is evidence of genuine remorse this may be taken into account. So too youth, old age, or ill-health may be relevant factors.

If a victim impact statement is made, this is considered by the judge. Not all victims who are entitled to do so avail of the opportunity to address the court. Of those who choose to submit a statement, not all express punitive sentiments.

Concurrently vs consecutively

When the judge is ready to pass sentence, consideration must be given to any statutory limits that apply and to the range of sentences imposed in similar cases. If there is more than one conviction to be dealt with, a decision must be made about whether the sentences will run concurrently or consecutively.

Attention will have to be paid to the underlying purpose of the sentence. Is it to be purely retributive? Should there be an element of denunciation? Should it focus on deterrence or rehabilitation? Is there scope for restorative justice?

Sentencing ought to have an educative function. The public should know that a measured response has been taken in their name. Offenders should know that their treatment is not arbitrary. Victims should know that the harm they suffered was taken seriously.

The level of dissatisfaction that erupts when high-profile cases come before the courts and apparently inexplicable decisions are made, suggests that more could be done to foster awareness of the sentencing process.

Having sat as a magistrate on the Oxford bench for several years, I can attest to the complexity of the decision about how much punishment is enough and the need for good-quality data to inform sentencers as well as those affected by their decisions.

If the public is to be reassured that the system is fit for purpose, it needs to learn about the ingredients of a proportionate sentence and how they are mixed in particular cases. This will require the provision of more information on court outcomes than is currently available.

It will never be possible to satisfy every observer on every occasion but it seems reasonable to strive for a situation where valid public concerns are not exacerbated by incomprehension.

Ian O’Donnell is professor of criminology at University College Dublin