What UX really is, and the design process

UX (user experience) is how it feels to use a product to get something done: is it useful, easy, efficient and pleasant? UI (user interface) is the visual and interactive layer: layouts, typography, colour, components, states. A product designer does both, plus product thinking.

The double diamond

1. Discover (diverge): research users, their context and pain points.
2. Define (converge): synthesise into a clear problem statement.
3. Develop (diverge): explore many solutions; sketch, wireframe, prototype.
4. Deliver (converge): test, refine, hand off, measure.

It's not strictly linear; you loop back whenever you learn something.

Problem statements and "How might we"

A good problem statement is about the user, not the feature:

Final-year students applying to many jobs struggle to track where each application stands, so they miss task deadlines and follow-ups.

Turn it into opportunity questions: "How might we make every application's next step obvious at a glance?"

Measuring UX

• Task success rate and time on task from usability tests.
• Error rate (wrong taps, validation failures).
• Product metrics: conversion, activation, retention, drop-off in funnels.
• Attitudinal: SUS (System Usability Scale), CSAT, NPS, qualitative feedback.

Design decisions should tie to one of these, which is exactly what interviewers probe.

Usability heuristics (Nielsen's 10, short version)

1. Visibility of system status (loading, saved, sent).
2. Match the real world (users' words, not internal jargon).
3. User control and freedom (undo, cancel, back).
4. Consistency and standards.
5. Error prevention (disable impossible actions, confirm destructive ones).
6. Recognition rather than recall (show options; don't make people remember).
7. Flexibility and efficiency (shortcuts for experts).
8. Aesthetic and minimalist design.
9. Help users recognise, diagnose and recover from errors (clear messages with a fix).
10. Help and documentation.

Practise by auditing apps you use daily against these: it makes great interview material.

Check yourself

• Explain UX vs UI with an example from a food delivery app.
• Write a problem statement for a college fee-payment portal.
• Which heuristic does a missing "undo" violate?