What is the test for determining whether a retireer's earning capacity has been diminished or diminished by a job-related injury?

In our view, the decision to retire implicates the element of "willingness to work" in the earnings-capacity calculus, and the primary factual [68 Cal.App.4th 848] component of the analysis must be whether the worker is retiring for all purposes, or only from the particular employment. (See Van Voorhis v. Workmen's Comp. Appeals Bd. (1974) 37 Cal.App.3d 81, 90, 112 Cal.Rptr. 208 ["matter of common knowledge" people often work at other jobs after retirement].) If the former, then the worker cannot be said to be willing to work, and earnings capacity would be zero. If the latter, then it would be necessary to determine an earning capacity from all the evidence available. A subsidiary question is whether the decision to retire is a function of the job-related injury. If the injury causes the worker to retire for all purposes or interferes with plans to continue working elsewhere, then the worker cannot be said to be unwilling to work and would have an earning capacity diminished by the injury. Thus, the worker may establish by preponderance of the evidence an intent to pursue other work interrupted by the job-related injury. ( 3202.5, 5705; cf. West, supra, 79 Cal.App.2d at p. 726, 180 P.2d 972 [burden on worker to explain reason for periods of unemployment].)