Systems implementation & evaluation

1. What is systems implementation?
2. What are the issues to consider before an information system is operational?
3. What are the key indicators of a quality system?

Systems implementation is the process of:

1. defining how the information system should be built (i.e., physical system design),
2. ensuring that the information system is operational and used,
3. ensuring that the information system meets quality standard (i.e., quality assurance).

Systems design

Conceptual design – what the system should do

Logical design – what the system should look to the user

Physical design – how the system should be built

Implementation issues

1. Testing

2. Conversion

3. Documentation

4. Training

7 types of tests

Test	Description	Characteristic
Inspection	Manually examine code for errors	Detect 60 to 90 percent of defects
Walkthrough (Figure 20.1)	Manually review code to find errors by examining what the code does	Should be done when the pieces of work are small
Desk checking	Manually work through the code, executing each instruction using test cases	The reviewer acts as a computer
Syntax checking	Uncover syntax errors by a compiler	The only automated testing technique that is static
Unit/module testing	Discover any error that may exist in a module's code	Each module is tested alone
Integration testing	Discover any error that may exist by combining modules	Top-down gradual testing
System testing	Discover any error that may exist by integrating programs into systems	Top-down gradual testing

Testing process (Figure 20.27)

1. Program testing with test data
2. Link testing with test data
3. Full systems testing with test data (alpha test)
4. Full systems testing with live data (beta test)

Testing guidelines

§ Test different aspects of the system, e.g., response time, response to boundary data, response to no input, response to heavy volumes of input

§ Test anything that could go wrong or be wrong about a system

§ Test the most frequently used parts of the system at a minimum

§ The people who create the test cases should not be the same people as those who coded and tested the system

§ Use debugging tools, e.g., symbolic debugger

Conversion strategies (Figure 21.12)

Strategy	Pros and cons
Direct/abrupt/ cold-turkey	§ risky § least expensive
Parallel	§ less risky § expensive § confusing to users
Gradual/Phased/staged	§ more manageable § requires careful version control
Modular/Pilot/single location	§ middle-of-road approach § limits potential damage and cost

Types of documentation

System documentation à maintenance programmers

Records detail information about a system's design specifications, functionality (external), and internal workings (internal), e.g., DFDs, ERDs, Structured English, Structure Chart, Pseudocode.

User documentation à end-users

Records information about an application system, how it works, and how to use it, e.g., user manual, procedure manual

Documentation standard

1. Compatible
2. Comprehensible
3. Informative
4. Adequate
5. Structured
6. Maintainable

Training guidelines (Figure 21.11)

1. Consider who will be the trainer and trainee
2. Establish measurable objectives
3. Use appropriate training methods
4. Select suitable training site
5. Use understandable training materials

Training topics

1. Use of the system

2. Computer concepts

3. IS concepts

4. Organizational concepts

5. System management

6. System installation

Training methods

1. Local experts: 51%

2. Computer-aided instruction: 17%

3. On-line help: 10%

4. Course: 10%

5. Tutorial: 7%

6. External sources: 5%

Quality assurance – to ensure that the system actually developed meets current and projected needs of the users and the organization

Total quality management approach to quality assurance:

• To build systems correctly from the start
• To detect and fix errors as soon as possible

Indicators of a quality system

1. Structured: top-down in design; modular in programming
2. Documented
3. Tested
4. Maintained, and
5. Audited

Structured system = structured analysis + structured design + structured programming

Structured analysis: input-process-output

Structured design: modular

Structured programming: sequence-selection-repetition