What is the difference between payments of workmen's compensation and retirement benefits?

Payments of workmen's compensation and of retirement benefits are based upon entirely different principles. The former is compulsory under state law; the latter is voluntary and is subject to contractual arrangement between the employer and employee. The former must be entirely subsidized by city tax monies where the employer is a city (City of Los Angeles v. Ind. Acc. Com. (Fraide) 63 Cal.2d 242, 46 Cal.Rptr. 97, 404 P.2d 801) or by the employer himself, through insurance or otherwise, where the employer is not a public body. Retirement pensions are considered to be an element of contractual compensation earned by the employee (Abbott v. City of Los Angeles, 50 Cal.2d 438, 455, 326 P.2d 484) and may include employee contributions.