text: 113. Policy and strategy formulation. The formulation of a strategy or adoption of a policy mix for the solution of multiple problems depended upon knowledge of the interrelations between and among variables. As goals and objectives might conflict with each other, so might the policies deemed to attain those goals and objectives. Indicators were needed to show to what extent a certain or specific policy contri­ buted to the solution of another problem or the attainment of another goal. That knowledge required that the determinants or causes of pro­ blems were identified and the process of attaining the goals outlined. These requirements meant that arrays of development indicators were not, of themselves, adequate for planning purposes. The necessary linkage between indicators and planning was analysis and interpretation of indicators. That stage required that a theory of development be specified and that models which could simulate the theory be employed. 114. It was essential that models of development specify the source of inputs to various areas of social concern. The success of some de­ velopment plans depended to a large extent on the exploitation of natural resources or upon foreign aid. Those sources of input were not generated by a country's own development process and were frequently non-renewable. 11 S. Programme and project identification, monitoring and evaluation . Traditionally, programmes and projects were selected with the use of cost-benefit or profitability ratios. Those, however, did not measure the desired impact of programmes and projects on the attainment of goals, especially social goals. Social indicators and analytical models were needed to project not only the economic but also the social impact of programmes and projects before they were implemented. 116. Monitoring was a very important aspect of development planning. Social problems were so complex that it was rare that theoretical models 
analysis: The text discusses the formulation of policies and strategies for development planning, which involves identifying the determinants of problems, specifying a theory of development, and using models to simulate it. It also mentions the importance of monitoring and evaluating the impact of programs and projects on social goals. This suggests that the text is focused on development planning in general, rather than a specific sector or field.