Design KPIs and UX Metrics

This article is an upcoming part of Smart Interface Design Patterns??? and will be a part of the?live UX training in September?as well. Just sayin’ ;-)

Design isn’t art. It solves problems. So we should be able to measure how well a particular design solves a particular problem. That’s why for the last few years, I’ve started setting up?design KPIs?for every project.

These KPIs inform, shape and restrict design decisions. They also?remove personal biases?and preferences out of equation. Instead, we improve UX, by testing and measuring it over time.

For design KPIs to be established, we need a clear understanding of the business KPIs, and how we can fit our design KPIs into the bigger picture of the business.

The Danger of Hidden Costs

Over the decades, we’ve become remarkably good in digital design. We’ve learned how to craft truly beautiful interfaces and well-orchestrated interactions. And we’ve also learned how to encourage action to meet project’s requirements and?drive business metrics. We can make pretty anything work really.

In the mock-up above, the option "Add to basket" is beautifully highlighted in green, indicating a way forward, with insurance added in automatically. That’s a deceptive pattern, of course. The design, however, will drive business KPIs, i.e. increase a spend per customer. But it will also generate a wrong purchase. The implications of it for businesses might be severe and irreversible — with plenty of complaints, customer support inquiries and high costs of processing returns.

Many organizations focus on a few selected business metrics; yet they need a holistic overview of metrics that have an impact on the entire business. As Paul Boag explains?in his recent book, there are plenty of?hidden costs?that often stay in the shadows of business KPIs. This usually leads to short-term improvements with expensive long-term implications.

A?healthy business metrics mix?usually includes KPIs that go a bit beyond data from Google Analytics. We also need to consider life-time value, time to first purchase, time to upgrade, loss in processing returns, cost of support, sales, marketing, acquisition and ratio of negative reviews, to name a few.

And that’s exactly where another significant set of metrics comes into play — design KPIs.

Frequent Design KPIs

1. Top tasks success rate > 80% (for critical tasks)

2. Time to complete < 35s (for critical tasks)

3. Average time to relevance < 30s (for navigation and search)

4. Search results relevance rate > 80% (for top 100 search queries)

5. Search query iterations < 3/query (to avoid dead-ends)

6. Relevance of top 100 search requests > 80% (search quality)

7. Average frequency of errors < 3/visit (mistaps, double clicks)

8. Error recovery speed < 7s (effectiveness of error messages)

9. Accuracy of sent data ≈ 100% (input by customers in forms)

10. Sales/marketing costs < $15K/week (poor design -> increased costs)

11. Time to first success < 15 sec (onboarding)

12. Service desk inquiries < 35/week (poor design -> more inquiries)

13. Service desk response time < 12h (speed of processing)

14. Customers follow-up rate < 4% (quality of service desk replies)

15. “Turn-around” score < 1 week (frustrated users -> happy users)

16. Environmental impact < 0.3g/page request (sustainability)

17. Flesch reading ease score > 60 (readability)

18. System Usability Scale > 75 (overall usability)

19. WCAG AA coverage ≈ 100% (accessibility)

20. Core Web Vitals ≈ 100% (performance)

These KPIs aren’t chosen randomly. They are shaped by?conversations with stakeholders?and users, and they must be aligned with business goals and company’s objectives. Ultimately, I try to drive business goals?with the help of?usability, rather than?despite?of it. Design and UX, then, are seen as an?enabler?of the business success.

How To Measure Design KPIs

Once we have defined the KPIs, how do we measure them? We can rely on Gerry McGovern’s?Top Tasks approach?and identify the most frequent tasks that users complete in a product. We conduct research to discover the?most important tasks. We study search queries and server logs, run user interviews and workshops with stakeholders.

Once we have that list, we bring users in to vote on the tasks that they consider to be important for them. Then we write down?task instructions?for each top task. These instructions will be handed to users in usability tests to validate that they can actually complete these tasks successfully.

Finally, we run tests with the?same task instructions?to the same segments of users, repeatedly, every 8–12 weeks. Based on these tests, we measure and plot success rates and completion times over time. As long as we improve our design KPIs, we should be on the right path. And we have data to prove it!

Design KPIs help us stay on track in driving metrics that actually matter. With them, we can?gradually improve UX over time?and gain evidence that our design decisions are actually effective in practice.

Let’s take a look a some examples:

• Usability of forms. You might want to track how accurate the submitted data is, how much time users need to complete it, as well as frequency of errors and error recovery speed.
• Usability of search. We identify?top 100 search requests?in a given year, and check with content editors what pages these requests should return. Then we track if “good” answers actually appear in?top 3 search results?for matching queries.
• Costs of service. We track the number of?service desk inquiries, phone calls, customer follow-ups and marketing costs. Good navigation and good search should help reduce all of them.

For a given project, around?3–4 design KPIs?will be most critical, and there will be around 4–5 further KPIs being measured over time. The process will be?repeated every 4–6 months, along with user interviews to understand how well and how fast users complete their tasks.

Every design team within the organization usually has their own?tailored set of custom KPIs. The success of each team is then assessed by how well they are performing across their own KPIs.

Wrapping Up

These KPIs aren’t rules; they are ambitious guidelines. They provide us with arguments to make the?right design choices. In fact, we can use them to make a case about how much money and time we have saved with the new design.

Then it’t not a matter of what somebody likes more; it’s a matter of what’s more cost-efficient and successful for the organizations. And?this argument wins in every single meeting.

Useful Resources

• The Ultimate Guide: Product Metrics 101 + PDF, by Pawe? Huryn
• All Product Metrics Explained, via Stéphanie Walter
• UX Metrics, by Roma Videnov
• OKRs vs. KPIs: What's The Difference
• OKRs for designers and design teams, by Aviram Vijh
• UX Metrics: Quantitative Research, by Krisztina Szerovay

Coming Up: Interface Design Live UX Training (Sep 8–Oct 6)

We’ll explore how to define, set and track?design KPis?over time in the?upcoming live UX training, coming up in September this year. With 8 live sessions, real-life UX challenges,?personal 1:1?feedback?and UX certification. Ah, you can get?just a video library, too.