System Analysis Lecture notes

Systems Analysis

Systems analysis includes a review of the present information system to assess its capabilities and shortcomings; specification of system goals, objectives, and constraints; a survey of potential system users to assess their information needs; identification and analysis of alternative system concepts; specification a system concept; and system requirements analysis and specification.This phase includes an analysis of major system functions and the development of a system

architecture (identification of the major system components and their interrelationships). Heavy emphasis is placed on end-user requirements. It is essential to involve the end-user in the system requirements activity, to insure the development of a system that is fully responsive the user's needs. The review of the current system and survey of potential users can be done by a

variety of means, including review of documentation, site visits, questionnaire surveys, interviews, and focus-group discussions.

Systems Design

The systems design phase is generally broken into two subphases, top-level design and detailed

design. Top-level design consists of the identification of the major system components and their

functions. In order to specify the top-level design, a number of alternative system design concepts

are synthesized and evaluated in terms of a variety of selection criteria, which include cost

(implementation, operation and maintenance), performance, satisfaction of requirements,

development risk, flexibility for expansion/upgrading, and political acceptability. The important

aspect of top-level design is to present several feasible solutions to the system managers and

users, to describe their advantages and disadvantages, and to obtain a consensus on a preferred

design concept. An example of a design decision is the decision concerning which functions

should be implemented using computers and which should be manual (e.g., should data collected

at a regional level and needed at a central level be transmitted via the Internet (e.g., virtual private

network or e-mail) or hand-carried on a memory stick).

Systems Implementation

Systems implementation consists of developing all of the system components -- data collection

forms; data collection, transfer and processing procedures; data entry procedures and screens

(including on-line edit checking); software; report forms; report distribution; quality control

procedures. As mentioned, we recommend the use of an iterative, rapid-prototyping approach to

the software implementation. It is highly recommended to field-test major systems in a single

geographic area before going full scale. This field testing involves not only software, but all

aspects of the system (e.g., data collection procedures, training, quality control).

Detailed design consists of specifying all of the system components and functions in detail. In the

detailed design phase, decisions are made concerning what data elements are to be collected,

how they are to be coded, how frequently they are to be collected, and at what levels of detail they

are to be aggregated. A critical design decision concerns the "units of analysis" -- the item on

which the data are to be measured, such as an individual, a household, a school, a clinic, a farm, a

village, or a region. The decision on the unit of analysis has a significant impact on both the cost

of the system operation (especially the data collection burden) and on the flexibility of ad-hoc

reporting. This design decision is particularly important. While it is an easy matter to revise a data

entry screen or report format, it is not possible to produce a desired report about a particular type

of unit if data on that unit are not included in the data base. For example, if it is desired to produce

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a report about the frequency distribution of villages by some characteristic, village-level data must

be included in the data base (or capable of being constructed by aggregation of lower-level units).

If it is desired to produce a frequency distribution of facilities by size, facility data must be included.

If it is desired to produce distributions of families with particular characteristics, data on families

must be included in the data base.