It has been estimated that only 20% of learning relevant to the jobs of individuals occurs in formal education and training situations (either on or off-the-job). Consequently, some 80% of relevant learning must occur in informal ways which are largely unmonitored and not fully researched. It is suggested that the Pareto Principle of Management Development in which 80% of the effort (on courses) produces 20% of the pay-off, but 20% of the effort (on other activities) produces 80% of the pay-off.