Design starts with who uses it and why
A user is a person who uses a system to get something done. Good interface design starts by finding out who those people are and what they are trying to do.
A shop built for the people who made it will suit the people who made it. This lesson shows you how to describe real users and pick the tasks that matter.
By the end of this lesson
Note
I can describe who uses a system and the tasks that matter most to them.
Key words
| Word | What it means |
|---|---|
| User | a person who uses the system to reach a goal |
| Persona | an invented but realistic user that stands for a group |
| Task | one thing a person wants to get done |
| Scenario | a short story of one persona doing one task |
| Frequency | how often a task is done |
The cells students fill in are left blank in this preview.
A persona stands for a group of users
You cannot ask every user what they need. A persona is an invented person, built from what you learn about real users, who stands for a group.
A persona has a name, a goal, a setting and something that may get in the way. It keeps a team asking "would Asha manage this?" instead of "would I?"
Worked example: two personas for a teapot shop
| Persona | Goal | Setting | What may get in the way |
|---|---|---|---|
| Asha, 19, a student | Buy a gift for her aunt before Friday | A phone, on a bus, with little data | A small screen and a thumb |
| Mr Okoye, 68, retired | Buy a replacement lid for his teapot | A laptop at home, at a large text size | Faint text and a mouse he finds hard to use |
The cells students fill in are left blank in this preview.
A task is one thing to get done
A task is one thing a person wants to get done, written as a verb and a thing: "find a teapot", "pay for the basket".
A task is not a feature. The shop has a search box, but the task is "find a teapot under 20 pounds". Tasks are what you test later, so write them from the person's side.
Look at the first rows of the test
docker exec jupyter head -5 sessions.csvShown here, not run. Create a free account to press Run and type it into your own lab’s terminal.
One row for each person and task
The command prints the header line, then four rows for the first person, P1: one for each task the lab's test gave. A row says how many seconds it took, whether the person finished, and how many mistakes they made.
The four tasks are the shop's main jobs: find a teapot, add it to the basket, fill in the form, and fix an error.
Count the lines of the table
docker exec jupyter wc -l sessions.csvShown here, not run. Create a free account to press Run and type it into your own lab’s terminal.
A scenario puts a persona in a situation
A scenario is a short story of one persona doing one task. It says who, where, why and what success looks like.
Example: "Asha is on the bus home. She needs a gift for her aunt by Friday. She finds a teapot under 20 pounds and pays with one hand." You can test a page against that story.
A common mistake
Warning
Many people think that they are the user. You know how the product works, so the path that looks obvious to you is not the one a new user takes. Ask real people, or build a persona from what you learn, and keep your own habits out of it.
Test the tasks that matter most
You cannot test everything. Two questions pick the tasks that matter. How often is it done? And what is lost if it fails?
A task done every day by most users, such as paying, comes first. A rare task, such as changing a delivery address, can wait unless a failure is costly.
Worked example: choosing tasks from visits
| Task | Visits in a week | Share of all visits | Test it? |
|---|---|---|---|
| Search for a teapot | 400 | 40% | Yes, it is the most common |
| Pay for the basket | 250 | 25% | Yes, money is lost if it fails |
| Track an order | 150 | 15% | Yes, it creates many help calls |
| Change an address | 100 | 10% | Maybe, it is done by few |
| Redeem a gift card | 50 | 5% | Later |
| Send a message to the shop | 50 | 5% | Later |
The cells students fill in are left blank in this preview.
Going further
Think of somebody who would use your college's timetable page. Write a persona for them: a name, a goal, a setting and one thing that may get in the way.
Then write one scenario for that persona in three sentences. Ask a classmate which task in it they would test first, and why.