The top down approach assumes a high degree of top management involvement in the planning process and focuses on organizational goals, objectives and strategies. The logic here is that, above all, an information system needs to be responsive to and supportive of an organization‘s basic reasons for being. Hence the organization‘s goals should be the driving force behind development of all the computer systems. Thus, using top down approach, we begin analyzing objectives and goals of the organization and end specifying application programs and modules that are needed to be developed.
Various steps in top-down approach are as follows:
i. Analyze the objectives and goals of the organization in terms of profit, growth, diversification etc.
ii. Identify the functions of the organization and explain how they support the entire organization.
iii. Ascertain major activities, decisions and functions at various levels of hierarchy. It should be analyzed what decisions are made and what need to be made.
iv. Identify models that guide managerial decision process and find the information requirements for activities and decisions.
Prepare specific information processing programs in detail and modules within these programs. Also identify files and database for applications.