So far in this study we have assumed that undertaking a proposed project would have no effect on the market prices of goods and services. However, since the market economy consists of a complex network of inter-related output and input markets, it is possible, in principle, that undertaking the project will have wide-ranging effects on market prices. If the project’s output or input quantities are small relative to the amounts traded in the markets for these goods and services, the effects on market prices will be small enough to be ignored, on the grounds that including them would have no bearing on the outcome of the analysis. While this “small project assumption” is a reasonable one for many of the projects which the analyst will encounter, it is important to be able to identify circumstances in which price changes are relevant, and to know how to deal with them in the costbenefit analysis.