What does your app really do?…and other adventures in instrumentation

Caner Uguz

Product Designer at VividCortex


We are hiring!

"I'm hearing great things about our product comparison pages." 

"Nobody is doing previews anymore, it's all edit; that's what our app should be."

"Our product detail page is by far the most visited, we can't make any changes to that page."

"People just don't use our app on the phone, we get only 0.5% of hits from mobile devices."

"Data driven"

The Case for Instrumentation

Design decisions have expensive and ethical consequences. 

You need systematic and cost effective data collection in your decision making process. 








Instrumentation is research

Apply sound research practices

Use statistical methods to understand your data better


the design, provision, or use of measuring instruments.

cost effective source of information about users

Instrumentation is not direct observation.

Not this

More like this


Be more thoughtful about instrumentation

Improve the quality of your existing methodology


Are your questions




Are my users...

like... happy? 

able to find the page that let's them change their date of birth? 


Did my users... 

enjoy this article?

spend enough time on this article to read all of it?


How many times did my users...

hover over their profile picture?

go the previous page using browser's back button?


Click filter input

Enter 'xyz' word

Hit clear

Click search box

Enter same word

Actions vs constructs

User is feeling generous

User clicks the button to increase donation dollar amount from $2 to $3

Photo by elCarito on Unsplash


Action Value Average
Total number of hitting back and forward in browser 7 1
average time spent on pages 10(sec) 150
total number of pages 12 3
total click events on pages 24 12
total times hitting 'cancel' or 'esc'  6 1

Where are you getting this from?

  • Review feedback
  • Look back at past users with desired outcome
  • From literature
  • Past studies, linear regression

Read up on: Scale construction




Consistency of a measure

Mostly not an issue on the web if your interaction is programmed for it. 


i.e. Lists that appear in an order defined by algorithm


Are you measuring what you intend to

Very commonly an issue


  • Calendar view is a top visited page and therefore very important for users... or is it? 
  • There are over 4000 events collected in time picker over 5 hours! 
  • Most common list size is 20 because 80% of people choose 20

The data

Is your sample representative?

Photo by Kelly Neil on Unsplash

Is your sample size big enough?


Make a habit of looking at your data

Summary table



Box whisker plot

You can't simply compare numbers

Statistical Significance

What is the likelihood that the result is by chance? 

"After we pushed this change our 200 more people signed up per week"

Does not mean the difference is 'important'. 

If your sample size is smaller, the likelihood of chance is higher. 

What is your research plan?

Photo by rawpixel on Unsplash

What is your data like?

Are you asking the right questions?

What matters to your team?

How do you define success?

What is your desired outcome?

Photo by Eunice Lituañas on Unsplash

Can you instrument qualitative data?

Yes but... 


Depends on your content

Requires different methodologies

Potentially sensitive data

Works best with categorical inputs

Photo by PNG Design on Unsplash

Ask your own database

Run scripts that give you aggregated content about what your users generate

Use case: are your charts empty?


Very accurate false data

"Our page hits doubled!


... after you introduced forced pagination

Badly defined constructs

"Our users are very engaged with our content"


... because you made it difficult to navigate

Reinforcing biases

"90% of our users read stories about political party A" 

... because you decide which articles to show users

Reinforcing biases

"We made our prefix menu shorter" 

... by removing Dr. from the list for women "because it literally is never used"  

Evil patterns

"We increased viewership in more of our movies"


... because you made it harder to find favourites. 

Illegal activities and grey zones

"User A seems to be buying a lot of bags, let's show them 10% higher prices than others" 

"User B has a great fashion sense, I will keep track of what they are buying"

Don't be Facebook

Is instrumentation surveillance?

Photo by Siarhei Horbach on Unsplash

Further reading

It would be nice if all of the data which sociologists require could be enumerated because then we could run them through IBM machines and draw charts as the economists do.


However, not everything that can be counted counts, and not everything that counts can be counted.

William Bruce Cameron 1963 text “Informal Sociology: A Casual Introduction to Sociological Thinking

What does your app really do?

By Caner Uguz

What does your app really do?

Instrumentation combining academic research methodology and UX research.

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