What is the test for loss of capacity to earn income in the future?

In Brown v. Golaiy (1985), 1985 CanLII 149 (BC SC), 26 B.C.L.R. (3d) 353, [1985] B.C.J. No. 31 (QL) (S.C.), Finch J. (as he then was) gave a non-exhaustive list of considerations to assist in assessing what he called “loss of capacity to earn income in the future” (at paras. 1, 8): 1. The plaintiff has been rendered less capable overall from earning income from all types of employment; 2. The plaintiff is less marketable or attractive as an employee to potential employers; 3. The plaintiff has lost the ability to take advantage of all job opportunities which might otherwise have been open to him, had he not been injured; and 4. The plaintiff is less valuable to himself as a person capable of earning income in a competitive labour market.

The recent authorities emphasize that an award under this head is an assessment of the lost asset, not an arithmetical calculation of projected earnings, deductions for contingencies, and so on: Rowe v. Bobell Express Ltd. (2005), 39 B.C.L.R. (4th) 185, 2005 BCCA 141. The distinction for hourly wage earners appears esoteric, and the practical difference in result of the two approaches may be negligible; see e.g. M. B. v. British Columbia, [2003] 2 S.C.R. 477, 2003 SCC 53 at para. 50, McLachlin C.J.C.: [T]he value of a particular plaintiff's capacity to earn is equivalent to the value of the earnings that she or he would have received over time, had the tort not been committed.