IMS1805 Systems Analysis Topic 2: Introduction to some key techniques for systems analysis in IS

2 Recap of last lecture Modern IS are heavily dependent on digital IT Analytical techniques tend to reflect that dependency We will look mainly at technology-based analytical techniques; and trust you not to forget that they are not the only ones

3 Agenda Aim: To introduce some of the main analytical techniques used in IS Review and reflect on your own analyses and diagrammatic representation Examine the possible components of analysis of an IS (Note: now we go down to about 50 ft above ground level where we can start to see only IS analysis techniques)

Reflections on your analysis of two systems See examples of analysis from last week’s tutes (available on web site) Consider the nature of these analyses in terms of: Content Form of representation (Note selectivity involved in both these) Strengths and weaknesses of these representations?

5 Comparing your analyses Accuracy? Level of detail? Comprehensibility? Standards? Creativity and meaning?

6 Diagrammatic representations Comparison with text descriptions? Explanation of meaning? (Is a picture worth a thousand words?) Precision? Strengths and weaknesses? Standardisation in diagrams?

Analytical techniques used in IS Techniques have evolved to meet developer needs. For example: Pre-computing (up to 1950s) Early computing (1950s) Structured analysis (“Birth” of IS?!) (1960s) Relational database (1970s) “Soft systems” theory (1980s) Object-oriented computing (1990s) Internet/web-based computing (late 1990s/2000+) As needs have changed, the system elements included in the analysis have changed

8 Components of an Information System People Things Events Connections/linkages Rules/regulations/ standards Actions/activities Other systems Data/ Information

9 What can we include in analysis of an IS? (i) Data/information The central element to all IS; essential, but can be difficult concepts to represent Data can be observed and identified precisely, but information is intangible and impossible to observe Distinction between them is important but also subjective and therefore user-specific (The whole point of an IS is to change data into information, so understanding the distinctions is vital for a developer)

10 What can we include in analysis of an IS? (ii) Things Inanimate objects which are used in the system to do things. For example: Machines – IT-based Machine – non-IT-based Documents/forms/etc Office equipment These objects may be customised to suit the system, or the system may have to be designed to adapt to them (The characteristics of these objects will enable or constrain the way the system works)

11 What can we include in analysis of an IS? (iii) People People who do things as part of the system – ie active ‘components’ who make the system work and have some control over it People who use the system People who may not use the system, but who are affected by it and its usage (Not only do people do things to make the system work, but their attitudes and motivations towards the system may affect how it works)

12 What can we include in analysis of an IS? (iv) Other systems Other systems which our system depends on to provide some inputs Other systems which depend on our system to provide outputs to them Other systems who share some components with ours and whose operations may therefore be affected by ours (If two systems interact, where do we draw the boundaries between them?)

13 What can we include in analysis of an IS? (v) Actions/activities Actions which are done by the system or as part of the system May be tangible physical acts (eg record data input on a form) or may be intangible and unobservable (eg check the validity of the input recorded on a form) Actions in a system cause changes in the state of the data/information which the system contains

14 What can we include in analysis of an IS? (vi) Events Things which happen to a system or its components may lead to actions or the need for actions to be taken May be due to specific actions (or the lack of these actions), or may be simply due to the passage of time (eg library loan becomes overdue; fine becomes payable, etc) (Events are often associated with a change in the “state” of something in the system)

15 What can we include in analysis of an IS? (vii) Rules/regulations/standards Everything gets done to a standard or level of performance of some kind – formal or informal Formal standards may be given the status of rules or regulations All System functions will need to be done to an appropriate standard in order for the system to work effectively (What standard is appropriate, and is it the same for everyone involved in the system?)

16 What can we include in analysis of an IS? (viii) Connections/linkages Every element of a system is connected in some way to at least one other part of the system Connections may take many forms: Physical connection Cause/effect (influence of one thing on another) Relative position within a systems (hierarchy) Movement between (things/people/etc) Etc (Different types of connections between different components)

17 Summary Many types of components Blend of components and their relative importance will vary from one system to another Different analytical techniques will reflect the differences in the perceived importance of each component to the system Next lecture: Look at some of these techniques and note for each one what emphasis they give to each of these components