Requirements determination and requirements structuring are two core components of system analysis. Traditionally, interviewing, questionnaires, directly observing and analyzing documents are four main methods adopted by system analysts to collect information. JAD and prototyping are two modern requirements determination methodologies, which are developed and based on the previous traditional methods. A well-structured representation of system requirements can dramatically improve the communication among analysts, designers, users, and programmers. DFD, structured English, decision tables, decision trees, and E-R diagrams are traditional primary requirements structuring tools. Nowadays, RAD and OOA are emerging to help streamline and shorten the total SDLC. While RAD SDLC packs traditional analysis phase and part of design phase into one step, OOA tries to make the outcomes of analysis phase can be reused by the following developing phases.
Analysis is the first SDLC phase where we begin to understand, in depth, the needs for system. System analysis involves a substantial amount of effort and cost and is therefore undertaken only after management had decided that the systems development project under consideration has merit and should be pursed through this phase. Most observers would agree than many of the errors in developed system are directly traceable to inadequate efforts in the analysis and design phases of the life cycle. Industry studies show that 56% of systems problems are based on poor requirements definition, as opposed to 7% that are caused by poor coding. In the maintenance arena, 82% of the effort is due to poor requirements as opposed to 1% for poor coding. However, for many reasons, it is difficult to obtain a correct and complete set of requirements.
As analysis can be divided into three main activities: Requirement determination, Requirements Structuring, and Alternative generation and selection. The third one is usually...