Revenue Canada would disagree with you. They deem anyone who gets over X%, and X varies depending on the economy, from a single source, you are not self employed, you are an employee. This was instituted in the early 70's when even people at the manager level would form Joe Smith Inc. and contract Joe Smith to the company he worked for, thus greatly cutting his tax liability. So the Alberta doctor's incomes are in most cases 100% single sourced. QED.