Year 10 · ICT · Spring 2
The systems life cycle; presentations · Lesson 1 of 5
Analysis and design
Theory7.1 Analysis7.2 Design
Year 10 · ICT · The systems life cycle; presentations · Lesson 1 of 5
You will learn to
- Describe observation, interviews, questionnaires and examining documents.
- Choose an analysis method for a scenario and justify the choice.
- Design a data structure with field names, field lengths and data types.
- Design an input form that is clear and easy to fill in.
Year 10 · ICT · The systems life cycle; presentations · Lesson 1 of 5
Success criteria
You have got it when you can say:
- I can give an advantage and a disadvantage of each analysis method.
- I can choose the best method for a vet's practice and say why.
- I can design the vet's record structure and its data capture form.
Year 10 · ICT · The systems life cycle; presentations · Lesson 1 of 5
Retrieval starter
Questions from before. Write your answers, then show them.
- Last unit
Non-contiguous data means…
A Numbers onlyB Ranges that are not next to each otherC A single column
B. Ranges that are not next to each other
- Last unit
Job sharing means…
A Two people share one full-time jobB Working from homeC Working nights
A. Two people share one full-time job
- Earlier this year
Chip and PIN checks…
A Your fingerprintB The chip, then the PIN you typeC Only your signature
B. The chip, then the PIN you type
Year 10 · ICT · The systems life cycle; presentations · Lesson 1 of 5
Key words (1 of 4)
- Systems life cycle
- The stages used to create a new system: analysis, design, development and testing, implementation, documentation, evaluation.
- Systems analyst
- The person who studies the current system and plans the new one.
- Questionnaire
- A set of written questions given to many people to collect their views.
Year 10 · ICT · The systems life cycle; presentations · Lesson 1 of 5
Key words (2 of 4)
- System specification
- A list of the hardware and software the new system needs.
- Field
- One item of data in a record, such as Surname.
- Coding of data
- Storing short codes such as M or F instead of whole words.
- Validation
- An automatic computer check that data is sensible and allowed.
Year 10 · ICT · The systems life cycle; presentations · Lesson 1 of 5
Key words (3 of 4)
- Check digit
- An extra digit calculated from the other digits, used to detect input errors.
- Data capture form
- A paper or on-screen form used to collect data.
- Test plan
- A table listing each test, its data, the expected and actual outcomes and any remedial action.
- Live data
- Real data from the organisation, used to test the system with known results.
Year 10 · ICT · The systems life cycle; presentations · Lesson 1 of 5
Key words (4 of 4)
- Evaluation
- Judging the finished system against the original requirements after it has been used.
7.1 Analysis · The explanation · step 1 of 9 · part 1 of 2
What a system is and why there is a life cycle
A system is a way of doing a job: the people, the data, the steps and the equipment.
The systems life cycle is the order of stages used to build a new system. Each stage feeds the next.
The stages are: analysis, design, development and testing, implementation, documentation, evaluation.
A systems analyst is the person who studies the old system and plans the new one.
7.1 Analysis · The explanation · step 1 of 9 · part 2 of 2
What a system is and why there is a life cycle (continued)
Working in stages means problems are found early, when they are cheap to fix. A mistake found after the system is live costs far more.
7.1 Analysis · The explanation · step 2 of 9 · part 1 of 2
Research method 1 and 2: observation and interviews
Observation means watching people use the current system.
Interviews mean asking people questions face to face, one at a time.
Both methods help the analyst understand the current system before designing a new one.
| Method | Advantages | Disadvantages |
|---|---|---|
| Observation | The analyst sees what really happens, not what people say happens. Reliable first-hand data. Fairly cheap: only the analyst's time. | People may work differently because they know they are watched (the Hawthorne effect). It can take a long time. Some tasks are not seen if they happen rarely. |
| Interviews | Questions can be changed during the interview to follow up answers. The analyst can see body language. People can explain problems in detail. | Very time-consuming, so only a few people can be interviewed. Expensive (analyst and staff away from work). People may give answers they think the analyst wants. Not anonymous. |
7.1 Analysis · The explanation · step 2 of 9 · part 2 of 2
Research method 1 and 2: observation and interviews (continued)
7.1 Analysis · The explanation · step 3 of 9 · part 1 of 3
Research method 3 and 4: questionnaires and examining documents
A questionnaire is a set of written questions given to many people, on paper or online.
Examining documents means reading the papers and files the current system uses: forms, invoices, reports.
Analysts usually use more than one method, so the weaknesses of one are covered by another.
| Method | Advantages | Disadvantages |
|---|---|---|
| Questionnaires | Reach many people quickly and cheaply. Can be anonymous, so answers are more honest. People answer when it suits them. Answers are easy to analyse, especially tick boxes. | Many people do not return them. Questions cannot be explained or changed. People may misunderstand a question. Tick boxes limit the answers people can give. |
| Examining documents | Shows exactly what data the system holds and the format it uses. Helps decide inputs and outputs. Does not interrupt staff. | Very time-consuming to read everything. Documents may be out of date or hard to understand. Costly, because of the analyst's time. |
7.1 Analysis · The explanation · step 3 of 9 · part 2 of 3
Research method 3 and 4: questionnaires and examining documents (continued)
7.1 Analysis · The explanation · step 3 of 9 · part 3 of 3
Research method 3 and 4: questionnaires and examining documents (continued)
In exam answers, give an advantage and a disadvantage that fit the scenario. 'It is quick' alone rarely earns a mark. Say quick compared with what, for example 'quicker than interviewing 600 students one by one'.
7.1 Analysis · The explanation · step 4 of 9 · part 1 of 3
What the analysis must find out
The analyst records the inputs (data going in), processing (what is done to the data) and outputs (results coming out) of the current system.
The analyst also lists the problems with the current system.
From this come the user requirements (what the users need the system to do) and the information requirements (what information the system must produce).
Finally the analyst writes a system specification: the hardware and software the new system needs.
7.1 Analysis · The explanation · step 4 of 9 · part 2 of 3
What the analysis must find out (continued)
| Item | Library example |
|---|---|
| Inputs | Student ID, book ISBN, date of loan |
| Processing | Work out the return date, check if a book is overdue |
| Outputs | Loan receipt, list of overdue books, reminder emails |
| Problems | Cards get lost, overdue books are not chased |
| User requirement | A librarian can record a loan in under 30 seconds |
| Information requirement | A weekly report of overdue books by tutor group |
| Hardware specification | PC, barcode reader, receipt printer |
| Software specification | Database software, operating system, email software |
7.1 Analysis · The explanation · step 4 of 9 · part 3 of 3
What the analysis must find out (continued)
The hardware and software choices depend on the requirements. For example, scanning book barcodes needs a barcode reader, and storing thousands of records needs enough storage.
7.2 Design · The explanation · step 8 of 9 · part 1 of 2
Input formats: data capture forms
A data capture form collects data from a person. It can be on paper or on screen.
A good form has a clear title, instructions, logical field order and enough space for each answer.
On-screen forms can use drop-down menus, radio buttons (choose one) and tick boxes (choose any). These limit what can be entered, so there are fewer errors.
Paper forms may use boxes with one character per box, so writing is easier to read or scan by OCR.
7.2 Design · The explanation · step 8 of 9 · part 2 of 2
Input formats: data capture forms (continued)
Exam answers about forms need specific features: 'use a drop-down for year group' earns a mark, 'make it look nice' does not.
The explanation · 4 more steps
More on the lesson page
The lesson page has the rest of the explanation, step by step:
- Designing the file structure
- Validation: what it is and why we need it
- The check digit, worked through
- Output formats: screen layouts and report layouts
Year 10 · ICT · The systems life cycle; presentations · Lesson 1 of 5
Quick quiz · 1 of 3
Parallel running means…
- A Old and new systems run together for a while
- B Testing in one branch first
- C Switching over in one go
A. Old and new systems run together for a while
Safe but twice the work. Direct changeover is quick but risky.
Year 10 · ICT · The systems life cycle; presentations · Lesson 1 of 5
Quick quiz · 2 of 3
Extreme test data is…
- A Outside the range
- B At the edges of the allowed range
- C Typical data
B. At the edges of the allowed range
0 and 120 for an age field. 150 would be abnormal.
Year 10 · ICT · The systems life cycle; presentations · Lesson 1 of 5
Quick quiz · 3 of 3
User documentation includes…
- A The database design
- B The program code
- C How to use the system
C. How to use the system
Technical documentation is for the programmers.
Year 10 · ICT · The systems life cycle; presentations · Lesson 1 of 5
Exit ticket
Answer on paper before you go. Then check.
Questionnaires are used in…
A AnalysisB ImplementationC Evaluation
A. Analysis Finding out how the current system works: observation, interviews, questionnaires, documents.
Editing the master slide…
A Changes one slideB Changes every slide at onceC Deletes the slides
B. Changes every slide at once Logo, colours, footer: set them once.