“…But for the saving in leisure time evaluation is made even more difficult by the lack of any such market, so that any attempt to price the saving must rely upon observations made of the extent to which individuals will substitute leisure for some other good that is priced. In the past attempts have been made to measure the rate of substitution between leisure and (1) wages (net of tax), (2) transport expenditure and (3) houses and transport expenditure. As has been pointed out elsewhere (Winchz2), all these approaches suffer from the fact that the substitution process often involves a third good (for instance, a commuter may choose the train not only because it is faster, but also because it is more comfortable).…”