3-Way Comparisons

Three-way comparisons are a convergent ideation method designers use to map their assumptions and tacit knowledge about familiar domains to new domains. They compare three related items in all possible combinations to uncover hidden attributes, understand the problem domain better and find insights to use innovatively.

“Resemblances are the shadows of differences. Different people see different similarities and similar differences.”

 — Vladimir Nabokov, Author and poet whose works include “Lolita” 

See how to use three-way comparisons to reveal powerful design opportunities:

Compare Three Things – Find More in Each

A vital skill underpinning a designer’s creativity is to bring tacit knowledge out into the open where it can be analyzed and insights shared. Sometimes, we have deep-held assumptions about designs, concepts, etc. These can range from an item’s smallest qualities up to critical factors of the mental model users adopt when encountering problems in context. If we take things for granted, we might overlook crucial points. That’s why it’s essential to isolate errors in how we envision design-related matters, and hopefully pinpoint previously unheard-of ways to access users.

Whenever we compare similar things, we can clearly map what makes them distinct as we systematically examine each’s qualities. The simplest way is to compare two items; by asking what’s similar and different, you can quickly compile a list. So, by identifying and discussing the distinctions between (e.g.) a menu on a webpage versus on a phone, you can make sense of the various characteristics of each.

However, a three-way comparison can help you uncover far more. This approach comes from the repertory grid technique used to map personality traits. It’s especially useful for exposing and expressing qualities which might otherwise lie buried under assumptions and bias. For example, you might compare a dropdown menu with a cascading menu with a pie menu. By starting with “How is A like B but different from C?” you proceed through different orders of comparison (e.g., “How is C like A but different from B?”). Consequently, you’ll force yourself to stretch beyond those obvious standard differences and engage the subjects more open-mindedly. In our video example, distinctions include:

• Grapes are smaller – one serving contains more of them. 

• Apples are contiguous, whereas oranges are segmented.

• Oranges are the “messiest” to eat.

• Grapes are to wine as apples are to cider – the priority you give helps define how you see the world.

By making these distinctions, you expose the categories you’ve involved. Also, when you list these inherent qualities, categories, etc., it’s far easier to spot new differences more easily and (potentially) new contexts of use.

How to Use 3-Way Comparisons

1. Pick three designs/products in the domain you’re interested in. (One of these can be your own if you work in that domain.) They should be similar, so you/your users must put effort into considering differences between them. If, for example, you’re designing a new user interface menu and you want to understand the domain better, you can choose three existing menu types for comparison: dropdown versus cascading versus pie. 

2. Compare each design to the other two. Here’s where you identify your own assumptions. Write down how each differs from the others. For example, from comparing how the dropdown differs from the cascading and pie menus, you notice a dropdown menu is horizontal and simpler.

Keep going as long as possible. If stuck, try considering a different dimension in which to compare the menus.

3. To make comparisons involving your users: Sitting down with one user at a time, show them the different designs and ask them to compare these: e.g., “Please list as many ways as you can think of how a dropdown menu is different from a cascading menu and a pie menu.” 

Write down what each user lists as different. Users will likely soon get stuck, but encourage them to persevere by assuring them that no comparisons are silly. You can also encourage them to compare the designs in other dimensions which they haven’t considered yet. (Note: As users can find this hard, it’s best to keep adding users until no new attributes are mentioned.)

4. Consider the lists of attributes in relation to the domain you want to design for: After making comparisons, you’ll have three lists of attributes (one for each design). If you’ve involved users, you should combine the users’ lists, so you have a list for each design that summarizes what every user said. 

Therefore, in the menu example, you have a list of attributes for each type of menu. Now go through each list and analyze how well this type of menu would work in your particular user interface. Do any attributes make it a good fit? Do any make it ill-suited? Have your users got any negative assumptions about a design that might make it problematic? Could you change the menu types somehow to make them fit better? 

Overall, remember that making three-way comparisons means you can dig deep beneath the biases and assumptions that we usually never voice because they seem so self-evident. This might be the deciding factor behind whether you accidentally sink time into an unremarkable idea or you pinpoint vital insights early on to power a truly innovative design. 

Learn More about 3-Way Comparisons

Our Creativity course includes three-way comparisons (and template).

This Smashing Magazine piece presents insightful angles on making more detailed comparisons.