3.9The development of a quantitative tool for measuring the harm caused or risked by an offence comprised four elements: (1) the identification of the interests harmed or put at risk; (2) the weighting of those interests in terms of their relative importance; (3) the development of a system for quantifying the level of injury to an interest; and (4) the development of a formula for identifying the overall harm score of each offence.
3.10The first step in developing a quantitative tool to measure the level of harm caused by the worst class of case of an offence was to identify the interests capable of being harmed by criminal offending.
3.12Physical integrity covers the physical health and safety of the individual. This interest is harmed by offences such as assault or murder, and may be jeopardised by offences such as drunk driving or breaches of health and safety laws. Material interests can range from the necessities of life, ie food, shelter, and clothing, through to luxuries, such as an MP3 player or a sports car. People also have an interest in avoiding breaches of personal privacy, and from being subject to humiliation or offensive behaviour by the actions of others.
3.14For the purposes of this review, therefore, we added these two interests to the three interests initially identified. This gave a total of five interests capable of being injured by an offence:
3.17We originally attempted to weight the interests by simply ranking them in order of importance and giving them a base value from 1 to 5. However, we quickly realised that this did not reflect the relative differences between them in terms of importance. We therefore undertook a more elaborate exercise to ascribe values to each interest.
3.18First, we devised three offence scenarios for each interest that in our judgement substantially harmed or risked harm only to that interest, and did so to a high, medium or low degree respectively (a total of 15 scenarios in all, which are attached as Appendix A). We did this because, as noted above, offences typically cover a broad spectrum of behaviour and can differ markedly in their range of seriousness. It was therefore necessary to arrive at a weighting that properly reflected the relative significance of an interest across the full range of behaviour to which it related.
3.19Secondly, the three people undertaking the project within the Law Commission ascribed numerical scores between one and 50 to each offence scenario depending upon the assessment of the harm caused or risked by the offence scenario by comparison with the other scenarios.
3.20Thirdly, the offence scenarios were given to two individuals as a pilot, and (after some modification) to 21 other members of the public that we identified through personal contact. We asked those respondents to give each scenario a score between one and 50 on the same basis. Although the respondents were not a representative or random sample of the population, they did represent a fair cross-section of New Zealand society: nine were from Wellington; four from the main cities and eight from provincial towns or rural areas; 13 were New Zealand Europeans and eight were Maori, Pacific Islander or Asian; 13 were females and eight were males; and the ages ranged from 16 to 75.
3.21Fourthly, four members of the "Sentencing Establishment Unit" (a Unit within the Law Commission established to draft sentencing guidelines for the inaugural Sentencing Council) were then asked to do the same exercise, giving a total of 25 respondents.
3.22The combined scores of all respondents for the three scenarios representing each interest were then added, and averaged to provide a single score between one and 50. In the light of the findings from this exercise, the initial scores of the three people undertaking the project were modified and reduced to a point on a scale from 1 to 7, representing the base value (ie the relative weighting) attached to that interest. These scores were as follows:
3.23Having determined the relevant interests and weighted their importance, we needed to decide how the level of harm that an offence caused or risked to an interest would be quantified.
3.24We decided that it was sufficient simply to score the level of injury to an interest by a value from 1 to 10. A score of 1 out of 10 constituted a nominal injury to the interest, while a score of 10 out of 10 constituted the most serious harm possible.
3.25Finally, we selected the formula for identifying the overall harm score which represented the harm caused to a single interest by the offence. This formula can be represented as follows:
If more than one interest was harmed by an offence, each harm score was added together to produce the total harm score for that particular offence. An example of how the tool worked is provided in Appendix B.