Wells Computer Consultants Ltd

Structured Systems Analysis and Design Method (SSADM) is an excellent method for evaluating the applicability of a software package to meeting the business requirements of a required system. Wells Computer Consultants adopts the SSADM approach to package evaluation.

The objective of any package evaluation is to establish which of the requirements are met in the required system specification and how well they are met i.e. with ease or by convolution and/or modification of the package. Some requirements may be identified as not achievable and it is then a decision for the business users to decide if the requirement was essential or just a 'nice to have'. Where the match is not exact what should change and what can be changed and the costs involved become criteria for package selection.

Penniless Porch. A full package evaluation is worth its weight in gold. Consult with WCCL for your package evaluations. info@wccl.co.uk

Before a full evaluation can be conducted the project must have produced a Requirements Specification (SSADM stage III) which is a collection of 'products' that define the required business logic and other features that the business users require. The evaluation process addresses the following:

• Comparison of the Logical Data Models. Logical Data Models identify the information that must be stored because of its importance to the business and the relationships that exist between sets of data. For example it is to be expected that a requirement for a sales order processing system is that customers can place orders and the system must reflect such relationships between information held about customers and orders. If a package does not provide details of the Logical Data Model there are available a number of Rapid Application Development (RAD) packages which can reverse engineer the Logical Data Model from the files or tables used by a software package.

• Comparison of the Data Flow Model. Data Flow Models identify the events to which a system must react, the information that must be available as a result of the event and how the information is processed and incorporated into the Logical Data Model. As in the previous example there must be a process that captures all the information required from a customer's order, but does the information captured by the package match the information specified as required? How is the order information incorporated into the Logical Data Model?

• Confirmation of Requirements addressed by the package. The Requirements Catalogue can detail many functional and non-functional requirements. For example functional requirements could include Business Objectives, System Solutions, Retrievals - enquiry and reports, new data to be included, System Interfaces. Non-functional requirements could include Service Levels, Access Restrictions, Security and Business, Financial or Operational Constraints.