How should the court assess a loss of earning capacity?

But how should the court assess a loss of earning capacity? The decision of Crimeni v. Chandra, 2015 BCCA 131, includes the following direction:

An award for loss of income earning capacity is intended to put the plaintiff in the position she would have occupied had she not been injured. It must be founded upon a real and substantial loss and must be measured by seeking to approximate the actual economic loss the plaintiff has suffered. The quantum of damages under this head has not been set or limited by convention, such as the non-economic heads of damages discussed by Dickson J. in Thornton v. School District No. 57 (Prince George) et al, 1978 CanLII 12 (SCC), [1978] 2 S.C.R. 267, at 284.