Chapter 1: Design for behaviour, not screens, lesson 2 of 6

Find the problems people don't report

People rarely tell you about their own mistakes. So how do you find them? Learn what counts as evidence, and why what people do beats what they say.

By 4 min read, 12 min of exercises

Warm-up

A quick one from lesson 1. Is each one a frustration, a motivation or an aspiration?

  1. I like being someone who never misses a payment.

    Right, it's aspiration. It's who they want to be. That keeps them coming back.

    Not quite. It's aspiration. It's who they want to be. That keeps them coming back.

  2. The app keeps logging me out, so I type my password again.

    Right, it's frustration. It costs them time, again and again.

    Not quite. It's frustration. It costs them time, again and again.

  3. I want to pay my bill before the late fee.

    Right, it's motivation. It gets them through today's task. Once it's paid, it's done.

    Not quite. It's motivation. It gets them through today's task. Once it's paid, it's done.

In lesson 1, you made a bet. How did Gmail’s team find out that people forget attachments?

Here is the honest answer: Google hasn’t said. But we can work out how a team could find out. That is what this lesson is about.

Think first

You work on an email app. You think people forget attachments. How would you find out if you’re right?

You

Which of these is closest to your answer?

Shirish

A survey tells you what people say. But would you write I forget attachments in a survey? Most people don’t notice their own small slips. They forget them.

So what could you look at, instead of asking?

Shirish

Interviews are great for many things. But people forget small mistakes fast. Ask someone about last week, and the missing file won’t come up.

What does a forgotten attachment leave behind, that you could see without asking?

Shirish

That was close to my first answer: interviews, surveys and data. But the data isn’t a plan yet. What exactly would you look for?

Name one thing a forgotten attachment leaves behind.

Shirish

Yes. That is the best answer here, and it’s where I landed too. Now make it exact.

People also send a second email to fix a typo. How would you tell a forgotten file apart from a typo?

You

What this means

Here is my answer. When people forget a file, they send the same email again soon after. Same person, same subject, a minute later, now with the file. You can count that without asking anyone.

Asking people works for many questions. It doesn’t work for mistakes they don’t notice. For those, you look for a trace: something the mistake leaves behind in what people do.

What a forgotten file leaves behind

When I was asked this, I thought about what I do right after I notice.

Shirishfrom my inbox

What I do when I forget to attach a file

When I forget a file, I don’t just shrug. If I can, I undo the send. If it’s too late, I send a second email. Same person, same subject, a minute later. This time with the file.

That second email is a trace. Here is what it looks like in a log:

A forgotten file leaves a trace: the same email sent again a minute later, now with the file. You can count it without reading a single email.

A team can count these traces. They never need to read anyone’s email, and nobody has to remember their own mistake.

Try it: find the forgotten files

Now you try. The log below has two forgotten files hidden in it.

Practice

Find the forgotten files

This is one person's email log for a day. You can't read the emails. They forgot to attach a file twice. Tick the 2 emails they sent without the file.

Clue: look at what happens right after each email.

Show the answers

The two forgotten emails are at 09:40 and 11:01. Each one is followed soon after by the same email with the file. The emails at 09:41 and 11:03 are the fixes, and 16:30 is a follow-up hours later.

A made-up log, written for this course.

Look at the email at 16:30. It has the same subject, but it comes three hours later with no file. So it is not a fix. A forgotten file shows up as the same email, to the same person, soon after, now with the file.

Not all evidence is equal

A survey, an interview and a log all give you evidence. But some evidence is stronger than others. This course uses a ladder to show how strong it is.

  1. 0 Opinion I think people forget files.
  2. 1 One story One person tells you they forget files.
  3. 2 What people say Several people say they forget files. A survey
  4. 3 What you saw You watched 5 people. 2 forgot a file.
  5. 4 What you counted The log shows 3 in 100 emails are sent again with a file. Counting second emails
  6. 5 It happened again Next month, the count is the same.
  7. 6 A fair test You added the check, and those second emails dropped.
The evidence ladder. The further down, the more you can trust it. You will use it in every chapter.

Asking people in a survey is rung 2. It’s what people say, and they may not know. Counting second emails is rung 4. It’s what people did.

You don’t need to learn the ladder by heart yet. Just notice this: what people do is stronger evidence than what they say.

My delete pop-up: evidence I never had

This one is about my own product, and it’s a little embarrassing.

Shirishfrom my own product

I didn't know if my delete pop-up ever helped anyone

In my code project app, deleting a project can cost weeks of work. So we show a pop-up: Are you sure?

When someone asked me if the pop-up had ever saved anyone, I had no answer. I said, I guess. I had built it on a guess.

Think first

Which trace would show that someone deleted a project and then regretted it?

You

Pick the answer closest to yours.

Shirish

Cancel shows they changed their mind before deleting. That’s useful. But what about the people who clicked through and regretted it later?

What would they do next?

Shirish

Yes. That’s the trace I landed on too. It shows regret after the pop-up failed to stop them.

What else could you count to back it up?

Shirish

Good, and easy to count. But it’s what people report. The people who never write in are missing.

What could you count for the ones who stay quiet?

You

What this means

Any of these is better than my guess.

So before you trust a feature, ask: what would people do if it failed? Then go and count that.

Words from this lesson

These words come back in every lesson. Here they are in one place.

Evidence
What people did, that you can see or count. In this lessonWe counted second emails with the file, instead of asking people.
Trace
Something an action leaves behind, that you can find later. In this lessonSomeone deletes a project, then makes a new one with the same name.
One story
One person’s report. A good place to start, but not proof. In this lessonOne person tells you they forget files.
Evidence ladder
Seven levels of evidence, from opinion at 0 to a fair test at 6. In this lessonAsking people in a survey is rung 2. Counting second emails is rung 4.

Back to your first answer

Your first answer

Your answer

Your answer will show here after you write one at the top of this page.

You've read the lesson. Would you change your answer?
Good. Which part of this lesson backs your answer?

Your bet: what does a workaround tell you?

Your bet

A teacher uses a coding app with his class. Each student builds one part of a game. He collects a link from every student. Then he copies each part into one project, by hand.

What does his copying tell you? Make your bet, and say how sure you are.

Your guess
How sure are you?

You'll find the answer in Lesson 3: Learn the words for what people do.

Try this during the week: pick one feature you use. What trace would show that it failed someone?

Sources

  • The evidence ladder is this course’s own tool. You will use it in every chapter.
  • The stories are from my own inbox and my own product.
Portrait of Shirish Shikhrakar

Written by

Shirish Shikhrakar

Shirish is a Google-certified UX designer and UX engineer based in Kathmandu, Nepal. He started as a software developer, moved into product design for Silicon Valley startups, and has taught UX foundations to hundreds of designers since 2019.

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