The dominant paradigm of industrial organization in the 1950s to 1970s. The structure of a market is the degree of monopoly power, often measured by the N-firm concentration index. Conduct refers to the behaviour of firms and the ways in which they compete. Structure combines with conduct to produce an outcome. The performance of the outcome can be judged against the efficient outcome. The paradigm faded from use when it was found not to be supported by empirical evidence.
Reference: Oxford Press Dictonary of Economics, 5th edt.