Calculation of damages: assessment of life expectancy
49 There remain for consideration the Appellant's challenges to the manner in which the trial judge assessed his damages. The first complaint was that her Honour had assessed his life expectancy by reference to "historic" tables rather than "prospective" tables, published by the Australian Bureau of Statistics. Any calculation of the life expectancy of a person alive today, based on "mortality rates" derived from past experience, involves a prediction of future events. Conjecture as to such matters should not be eschewed: see Malec v J.C. Hutton Pty Ltd (1990) 169 CLR 638 at 643. Nevertheless, generally speaking greater accuracy is to be preferred over known inaccuracy.
50 The factors which determine mortality rates are numerous. For example, it is standard practice to make separate assessments for men and women because females are recognised as having, on average, a greater life expectancy. Similarly, the present age of the individual may be relevant: if the average or mean life expectancy of men is 79 years, that does not mean an 80 year old man has no relevant expectation of further years of life. Similarly, as is apparent from life insurance practice, life expectancy may well depend on whether or not one smokes, has a particular disease, or a particular genetic characteristic rendering one susceptible to a specific disability. Thus, information about the particular individual may justify taking that individual outside the statistical norm.
51 The issue raised by the Appellant does not require an assessment of these various factors: rather it seeks to include in the calculation statistically verifiable increases in life expectancy over recent decades. Taking into account improving life expectancy will, according to the tables presented in evidence in the present case, give rise to an increased life expectancy which is some 5.6 years higher than is the case ignoring projected improvement in life expectancy in the future. The difference is sometimes referred to as the difference between using "historical tables" and the adoption of "projection tables". These terms tend to be misleading, as the only difference drawn to the attention of the Court was the adoption, in the latter case, of the additional calculation based on historically determined rates of improving life expectancy, themselves determined on past experience. The former table is based on ABS information in relation to deaths in a particular year, the latter is adopted for the purpose of one aspect of the prediction of the future population in Australia.
52 The trial judge was of the view that she should follow current practice, which is to apply tables based upon annual information with respect to deaths. In taking that course, she felt obliged to follow the approach of Studdert J in Beck v State of New South Wales [2001] NSWSC 278 at [132] where his Honour said:
"No evidence was called in this case concerning the two sets of statistics. Whilst I do not regard the argument for the projection tables as being unattractive, I have decided that I should employ the tables traditionally used in these matters, leaving it to an appellate court to determine, if such be considered appropriate, that the projection tables should be adopted. Any set of tables can only be a guide, and I propose to approach my task guided by the historical tables and providing for the plaintiff's needs for a further 45.2 years, since I determine such period reflects his life expectancy."
53 There are arguments in favour of following a traditional approach in assessing damages based on unknown events. In some respects, as will be noted below, those arguments are persuasive. They are based on two primary considerations: first, that the assessment of damages is an inherently speculative task, the exercise of which is not improved by apparent refinements and, secondly, that the choice of particular figures is in any event, to an extent, arbitrary. There is a third pragmatic consideration, namely that attempts to move away from standards statistics, in favour of a more individualised assessment, may well increase the costs of litigation without any guaranteed benefits in the end results. This last consideration is not relevant for present purposes, because the argument in relation to life expectancy is put upon the basis of statistical norms, not individual assessment.
54 In the case of life expectancy, the reasonableness of the calculation may be speculative, but the criteria adopted are not arbitrary. Rather, they are based on solid information in relation to past deaths. However, if there is further information, again based on past deaths, which suggests that the predictive figures are likely to change in the future, it is not obvious why such further information should be excluded. Indeed, that exclusion tends to render a rational, if imprecise basis of assessment more arbitrary than it needs to be. Of course, projected changes in life expectancy may prove to be misguided when future experience is known. However, the same can be said, with possibly a greater degree of certainty, in relation to reliance on information concerning past life expectancy without taking into account a statistical change which is already taking place and is measurable. Further, changes in life expectancy are not treated by the Australian Bureau of Statistics as arbitrary or irrelevant: rather, the Bureau relies upon them for the important task of seeking to estimate the future population of the country in decades to come. Nor was it suggested that the relevant figures were not publicly or readily available. They are published by the ABS on an annual basis and would be turned into accessible tables by those forensic accounting consultants which presently produce information as to life expectancy based on "historical tables".
55 On the basis that the projections of changes in life expectancy should be accepted as an appropriate estimate of life expectancy, there was no challenge by the Respondents to the figure relied upon by the Appellant. In my view it is appropriate for the courts to make their estimations on the basis of the best information available: the projected tables would appear to be a more accurate assessment of future trends than the historical tables. Accordingly, it would have been appropriate for the trial judge to adopt the projected table and the figure resulting therefrom, in the present case. According to the report prepared by Cumpston Sarjeant Truslove Pty Ltd, that gave a predicted life expectancy for a man of the Appellant's age as at 3 May 2004 as 54.28 years. (That figure had to be adjusted for any diminution caused by the injuries caused by the accident.)