Any determination of a "percentage of total incapacity" requires a comparison between the incapacity of the person at the time of the determination and an entire loss of capacity for these are the components which yield the percentage. A comparison in percentage terms requires the selection of the appropriate point upon a scale which runs from 0 to 100, a scale which runs from an undiminished capacity (0%) "in relation to civil employment" to a total incapacity (100%). A moment's reflection reveals the difficulty of the task which confronts the Authority. What is comprehended by the phrase "civil employment"? What is the nexus between incapacity and civil employment which is expressed by the phrase "in relation to"? The uncertain connotation of the terms may lead to unevenness in administration of the Act for the statutory test may take on different meanings in the minds of those who administer its provisions. It is necessary therefore to define the meaning of s.51(2) in order rightly to apply the relevant principles to the facts of the case.
"Civil employment" comprehends both an engagement to work, whether under a contract of service or for services, and the remuneration or benefits which are the tangible fruits of such an engagement.
"Incapacity" in relation to civil employment thus comprehends an incapacity in relation to the engagement of the person to work and in relation to the earning of remuneration and other work - associated benefits. Diminution in earnings is not the only criterion for determining the percentage of that incapacity - indeed there may be cases where there is a substantial incapacity affecting the employability of a person entitled to benefit which does not produce any, or any significant, effect upon his earnings. On the other hand, a relatively minor diminution in employability may entail a large loss of income, and occasion a substantial percentage incapacity.
"Incapacity in relation to civil employment" is a wider concept than the "ability to earn income". An "incapacity" may be said to be "in relation to" civil employment if the opportunities to engage in civil employment and to derive benefits from that employment are restricted by reason of the incapacity.
If there be no incapacity of the relevant kind, a person's talents - his education, training, skills, physical strength, personality or other attributes - open to him a range of employment opportunities. The range may cover opportunities for engaging in various kinds of employment, for earning various levels of remuneration and for deriving tangible and other benefits. These are the opportunities which are appropriate to the individual - his own range of employment opportunities estimated by reference to the talents which, but for the incapacity, he would have had. When he suffers an incapacity, some of these opportunities are denied to him. He suffers an incapacity in relation to civil employment. A comparison between the lost opportunities and the whole range of the individual's employment opportunities provides the measure of his percentage incapacity.
The comparison is made and the percentage of any incapacity is determined by reference to the importance which the lost opportunity has for the individual. That is not to say that importance depends upon the individual's subjective assessment of his incapacity, or upon his emotional reaction to the loss of the employment opportunity. An objective assessment is required which takes account of the circumstances peculiar to the individual. An objective assessment may reveal that a significant physical disability, e.g., the amputation of a hand, is of much greater importance to a man whose talents limit him to labouring than to one whose talents qualify him for clerical work. The loss of any employment talent is of more importance to one whose talents are only marginally sufficient to secure employment in good economic conditions, for he will assuredly lose employment opportunities in times of adverse economic conditions. However, the determination of percentage incapacity does not vary with the swing of the economic pendulum. Employment opportunities are estimated by reference to the talents which the individual possesses, and it should be assumed that the talents which he had and the talents which he would have had would give or would have given opportunities for employment in which those talents would be or would have been used. Once the extent of the lost opportunities is assessed, the importance of that loss may be assessed and the percentage incapacity thereby determined. Economic changes, or the prospect of economic changes, will have varying importance for the individuals whose percentage disability is to be determined. Events may prove the initial determination to be right or wrong. They may show that the percentage disability (which was determined after taking into account the various employment opportunities which were lost or likely to be lost) was determined at too high or too low a percentage. The error that thus becomes apparent may be corrected either on the application of the person entitled to benefit or by the Authority on its own initiative. But error will not be shown merely by the occurrence of an event which the Authority had already taken into account.