To better deal with uncertainty, service designers try to verify from different angles 🔎 that what they have learned about what people want and need actually reflects the truth. This is what they call triangulation.

Triangulation is a term to define that you try out multiple ways to see if they bring you to a similar conclusion.

As the smart contributors of Wikipedia show, triangulation is nothing specific to Service Design. Social sciences have used it for ages.

In 1978, Norman K. Denzin identified in his book "Sociological Methods: A Sourcebook" 4 types of triangulation:

1. Data triangulation 📊: involves time, space, and persons

2. Investigator triangulation 🥼: involves multiple researchers in an investigation

3. Theory triangulation 🧠: involves using more than a singular theoretical scheme in the interpretation of the phenomenon

4. Methodological triangulation 🛠: involves using more than a singular method to gather data, such as interviews, observations, questionnaires, and documents.

Many service designers typically use 3 different triangulation methods. The goal of these is to ensure that you didn’t jump to conclusion too quickly. Often, service designers don’t use the theory of triangulation, which is more suited in my opinion to academic work.

Methodological triangulation

Methodological triangulation means that you will try out different tools and see if you arrive at the same result.

It basically tells you to mix your tools 🛠, play with surveys, interviews, observations, and so on. If such different research method arrived at the same conclusion, there is a pretty good chance it’s a good reflection of what is actually happening in people’s lives.

I often recommend mixing tools different research families. It’s always great to have qualitative 💬 research tools, like interviews, and mix them with quantitative 📊 research tools, like surveys. I highly recommend doing so, as you are not only trying another approach, you are also using another approach from a whole different research mindset.

Investigator triangulation

Investigator triangulation means that you’ll ask different researchers to analyze the findings and look if they arrive to the same conclusion.

When you go through interviews, it’s quite easy that you end up interpreting what a person said from your own perspective and bias.

A "bias" is a term used in service in design that means that you have some tendencies to think in a particular way but you don’t notice it yourself.

To overcome these biases and be sure that the way you interpret what has been told to you is not only your way to see the world, it is pretty smart to bring in different people 👫 who will look at the raw data. So, you’ll ask a colleague or friend to go through the interviews and tell you what this is all about. If they find similar conclusions than you this is pretty reassuring, as even if they have a different worldview they arrive to the same conclusion.

Data triangulation

Data triangulation means that you’ll use different data source and see if they tell you the same story.

This one is pretty obvious. Let’s take the example of interviews. If you are using interviews to learn how a specific group of people think of and need things, you will not only speak to one person but multiple people. This is data triangulation.

In the case of observation, you do this in the street; to triangulate your data, you’ll come at different times ⏰ of the day to see if things are the same at the different times of the day.

Again, if you are making an observation about how people use a train station, you might be interested to not only look at one train station, but at many of them. This is what data triangulation is about.

The usage of triangulation is a great tool that service designers use in to kill uncertainty in an innovation project.