Build it twice, or write it once
Mia builds a live sales screen for the canteen. The manager says, "I wanted last week, not today." The cook says, "I cannot read it."
Mia never wrote down what was needed. A short specification would have saved a week.
Key words
| Word | What it means | Example |
|---|---|---|
| Specification | A written list of what a message or product must be and do. | A one page plan for a sales dashboard |
| Requirement | One thing the finished message must do or have. | Shows sales for the last 7 days |
| Factor | One thing you must think about when you plan. | Audience |
| Context | Where, when and why the message is used. | A wall screen in the dining hall |
| Format | The form a message takes. | A dashboard |
| Data type | The kind of data, such as numbers or words. | Numbers from the till |
| Benefit | A good result the reader or business gets. | Staff see queues at once |
| Dashboard | One screen of charts and figures that update as data changes. | Live queue sizes |
| Storyboard | A row of sketches or boxes that plan a message in order. | Four boxes for four screens |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can write a specification with the six factors, choose a format and explain its benefits clearly.
Starter: what you already know
Have a go
Starter: what you already know
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Step 1: identify the requirements
Ask the people who will use it. Write each requirement as one clear sentence you can check later, such as "shows the last seven days of sales" or "readable from three metres".
Separate what the message must do from what would be nice.
Step 2: apply the six factors
Cover audience, purpose, content, data type, context and review. Together they make a complete specification.
If one is missing, someone will guess, and guesses are the cause of rework.
A specification for the canteen dashboard
| Factor | What the specification says |
|---|---|
| Audience | Canteen manager and till staff, non-technical |
| Purpose | See queues and sales now, to decide how many staff to put on |
| Content | Sales so far today, queue size, three charts at most, no jargon |
| Data type | Numbers from the till, counted every five minutes |
| Context | A wall screen in the kitchen, read from three metres, in a busy room |
| Review | Staff use it for two weeks. We ask if it helped and check the figures against the till |
The cells students fill in are left blank in this preview.
Check: which factor is it?
Have a go
Check: which factor is it?
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.