Sankeys (or the allure of Alluvial diagrams)

So what’s this all about?

In this study, the brand commissioning the research is a manufacturer of consumer durables (electrical or whitegoods). The brand manufactured several tiers or types within their category, ranging from relatively low-involvement, through to more complex and more ‘hands on’. The category is broad – you could spend less than $100 as an entry point, through to over $3,000 for upper end models, features and specifications. Moreover, this is a category with a fair bit of fanaticism – plenty of folks wouldn’t bat an eyelid at spending over $1,000.

A core part of this study was understanding the customer journey to inform product design and marketing activity when the ~3 year upgrade cycle came around. Expanding on this, the client had specific questions about customer journeys:

• How many people moved from the simple to the complex?
• What drives people to spend more or less?
• Who are the types of people who stick to the same category, versus those who trade up or trade down?
• What are the motivations, behaviours and attitudes that drive this movement?
• What do these same people intend to do in future?
• What features and experiences do people look for, what spend do they anticipate, do they intend to experiment with something new or remain the same?

What’s the problem?

The first challenge was thinking carefully about study design. Asking people why they did something will turn up all sorts of post-rationalisation and half-truths.

Instead, we should really use the data and analytics to infer the movements and drivers. So what we did is understood the past, the present, and future. We then looked at how these things differ, rather than asking someone to tell us why they changed.

By deriving these needs, we help separate the fanciful and post-rationalised from the reality, and lean more heavily on the researcher and data analysis to uncover motivations than the consumer.

How do we solve this?

Thinking more on these points, you can see how quickly it gets complicated. Not just understanding movement from category entry point to current, or current world to future – but also the nuances of these journeys, and motivations.

To solve for this, we decided to use a Sankey Diagram (or Alluvial Diagram). Captain Matthew Sankey was an Irish Captain who used this sort of diagram to understand efficiency and energy flows of a steam engine. For the geeks reading this, Sankey diagrams are a visualisation of material flow analysis, which serves very nicely indeed to understand the major flows within a system. Put another way, it’s a great way to show customer journeys.

Shown below is a (deliberately) simplified Sankey / Alluvial diagram, with associated journey highlights. In our study we had more nuance within each type, and this was simplified for the purpose of this article. Not shown here, but included in the report is the detail that sits behind these flows. Each of the individual horizontal lines shown below indicate a cohort of individuals moving from one track to another, or remaining on one track. This is all colour-coded by where they end up / the destination. These individuals can then be profiled at depth: who they are, how they engage with the category, how much they have spent / will spend, what brands / models they own, what their needs are, the features they seek, etc.

It provides an elegant, and simple way, to visualise complex journeys, and identify the types of journeys and people we really want to dive into.

What’s the vibe?

The use of a humble Sankey diagram provided the basis of comprehensive analysis within this particular category. What started off as a way to visualise something complex became the backbone of our report.

It allowed the client to understand the customer journey between types of durable.

It allowed us to specifically highlight consumers who moved between these different types, and understand the motivations of either maintaining their trajectory, or modifying this trajectory.

In short, we wanted to celebrate Captain Sankey’s work, as it provided a firm foundation for this particular study, and was the basis of much of our analysis and subsequent product development decision-making for our client.

So when you next need to consider visualising customer journeys between different tiers within a category, think of the humble Sankey / Alluvial diagram and its ability to visually show complex relationships and movements.