Systems Development Methodology

'Systems Development Methodology' (abbre­viated SDM), also called 'cascade' model.

We pay attention to this method here because of three reasons.First of all, Systems Development Methodology was, and probably still is, a very popular information systems design method. Secondly, Systems Development Methodology has a rather bad reputation, not because of its intrinsic qualities but due to the way it is often applied. Thirdly, in connection with the two former points, Systems Development Methodology can, in our opinion, be very helpful in facilitating information systems' design. Though SDM, as a project control method, is more broadly applicable, we will only judge its usefulness from the point of view of the requirements in the field of informa­tion system design. To identify this usefulness we continue with a short discussion of Systems Development Methodology. Before doing so, we pay attention to the difference of organizing information projects and SDM. The subject 'organizing information projects' is especially about the structure of these projects; in other words the relations between players in the field and the rules they have to obey. SDM, however, refers to the process that, combined with adequate design methods, helps to attain the intended result.

SDM is developed by PANDATA, an agency for information systems design, founded by a number of large companies.

After a version draft in the mid seventies, in 1985 a revised version was published, well-known as SDM-II (Turner, c.s. 1985).

The assumptions of Systems Development Methodology can be summarized as follows:

• information projects are planned and developed,
• information projects are controlled and organized by splitting up these projects into manageable parts,
• Information projects are administered in detail, combined with extensive systems documentation.

As to this second principle we emphasize that it is not the intended information system the project result that is split up in a number of parts, but the design process - the project road - which is divided into several stages.

According to SDM we distinguish between the following stages:

• information planning,
• definition study,
• global design,
• specific design,
• realization,
• implementation,
• Exploitation and management.

Questionnaire:

• What is Systems Development Methodology? Explain.