Why we added a bowel chart to the app.

Design · 5 min read

I'm going to talk about poo. Specifically, I'm going to talk about why tracking bowel movements ended up being a feature in an NDIS life management app, and what it taught me about designing for things people don't want to discuss.

The client brought it up. He works in disability services and he sees it constantly. People on long-term medication get constipated. People with certain conditions have irregular bowel habits that need monitoring. Aged care facilities track it as a matter of course. But for people living independently with support, there's nothing. No easy way to log it, track patterns, or share the data with a GP.

So we added it. And the design challenge turned out to be more interesting than I expected.

The Bristol Stool Chart is real medical infrastructure

The Bristol Stool Chart was developed at the University of Bristol in 1997 by Dr. Ken Heaton. It classifies stool into seven types based on shape and consistency. It sounds ridiculous until you realise that it's used globally by GPs, gastroenterologists, and care providers as a diagnostic tool. It's in medical textbooks. It's referenced in clinical guidelines.

The problem is that the standard chart uses clinical photographs that are, to put it diplomatically, not something you'd want on your phone screen. And for users with cognitive disabilities or low literacy, clinical diagrams don't communicate clearly. We needed something that was medically accurate, visually clear, and not horrifying to look at.

We also couldn't just use the existing chart images. Copyright. So we had to create custom illustrations. Seven types. Accurate enough to be medically useful. Friendly enough that someone wouldn't close the app the moment they saw them. The client and I both laughed about it in the meeting. "We get to have fun with poo pictures." But it was a genuine design challenge with real constraints.

Why most apps avoid this

Nobody builds this because it's awkward. Health apps focus on steps, sleep, heart rate. The marketable stuff. Bowel tracking is unglamorous. It doesn't end up in the App Store screenshots. It doesn't make the pitch deck.

But if your users need it, you build it. That's the whole point of building from domain expertise. You don't pick features based on what sounds good in a meeting. You pick them based on what your users actually do every day. And for a lot of people in the care sector, tracking bowel movements is a daily reality.

The feature itself is simple. Time, type (tap one of seven illustrated options), done. No lengthy form. No description field. Just the data that matters. A GP can look at a month's worth of entries and immediately see patterns. That's clinically useful information captured in about five seconds per entry.

The broader lesson: build what's needed, not what's comfortable

Your app will have features that aren't sexy. Features that don't make the landing page. Features that nobody talks about at the pub. But they might be the reason someone keeps using your app every day instead of abandoning it after a week.

The test isn't "would I put this in the marketing?" The test is "does someone need this to do what they came to do?" If yes, build it. Design it well. Give it the same care you give the flashy features. Because the person who needs it will notice, and they'll stay.

And for what it's worth, we did have fun designing those illustrations. Sometimes the least glamorous feature is the most satisfying to get right.

Sources
Bristol Stool Scale - Developed at the University of Bristol (1997) as a medical diagnostic tool.
Scandinavian Journal of Gastroenterology - Original research by Heaton and Lewis on stool classification and transit time.

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The difference between a feature and a solution →

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