1. 1. An excellent historical perspective of the theoretical development of the free rider concept is provided by James Buchanan (1968, pp. 97-9); see also, Stigler (1974).
2. 2. Both Marshall , Cartter , and King (1976) and Burton (1977) have indicated that union security agreements and legislation existing in the U.S. are not prevalent in most of Western Europe. Burton specifically states that the private goods nature of labour union services ‘calls for the repeal of Section 9(a) of the Wagner Act. American unions would then be free, as they are in Britain, to provide their market bargaining and contract-policing and enforcement activities to their members only’ (1977, p. 7).
3. 3. This does not suggest that unions are able to achieve higher benefits for their members; it simply means that union-negotiated wage agreements are inflexible while the contract remains in force.
4. 4. Bradley (1976) indicates that the courts have supplied two different versions of the union benefit theory which do not yield the same result. The two interpretations are inconsistent because one claims that the union benefits all persons in the bargaining unit, while the other suggests that some persons may not benefit, i.e. only persons receiving benefits from union services should contribute to the cost of providing these services. Of course, the union must rely on the first interpretation for support of coercive dues payments.
5. 5. It has been shown in a recent article by Olsen (1978) that the specified parameters of the union membership equation and the wage equation employed by Schmidt and Strauss are related to each other by a linear transformation. This finding casts some doubt on the significance of the Schmidt and Strauss results, but does not alter similar conclusions reached by Ashenfelter and Johnson.