February 1, 2024

CRO: How to grow ecommerce sales using CX and behavioural science

Ruth Gwilt
February 1, 2024

CRO: How to grow ecommerce sales using CX and behavioural science

If you’re wondering how much you can possibly benefit from simple changes to the words or appearance of your call-to-actions, or slightly altering your user flow into checkout, you might be surprised to hear it could net you a cool $300,000,000*.

* Well, if you’re Amazon that is! But read on, it can help you too…

The $300,000,000 button

In 2008, Amazon hired UX wizard Jared Spool to investigate a high drop-off rate when converting customers to checkout. Analytical data could show where the drop-off was happening: at the log-in screen, but it took some user interviews to discover the Why.

Amazon thought that asking users to log in would allow them to enhance the customer experience and to capitalise on remarketing, but it was actually costing them dearly. By interviewing users, Spool found that new customers didn’t want to log in for fear of being spammed or due to the extra time it would take, while existing customers often couldn’t remember their password or even whether they had an account at all.

So they changed their “Log In” function to a “Continue” button and added an important note below: “You do not need to create an account to make purchases on our site.” Guest checkouts might seem obvious to Shopify merchants now but this was groundbreaking at the time, yielding the following reported gains for the ecommerce giant:

- 45% increase in customers purchasing each month

- $15million extra revenue from those purchases in that first month,

- $300million annual revenue increase

- And 90% of the customers ended up creating an account later in the purchase journey, a greater overall number than when login was mandatory to checkout!

Why does it work?

The success of this simple change is due to the following behavioural science principles:


We hate having our freedom threatened and will react against attempts to curtail our choices. Giving customers choice made them feel empowered and more positive about the purchase journey and about the brand.

Functional friction

If users encounter a hurdle, they will often abandon rather than overcome it. We see this time and again with account creation, login screens and forms which require additional data that isn’t easily accessible to the customer.

Cognitive effort

Everything you put in front of your customers increases their cognitive load, whether it is something to read, to recall or an action to complete. We must consider carefully the value of everything we ask customers to process; if it’s deemed too much effort for the perceived gain they will abandon the process


As a Shopify retailer, you already reap the benefits of Guest Checkout functionality so what can you take from this case study? As well as reiterating what we know about behavioural science, there’s some key points to ensure you build into your growth strategy:

Watch your data

Ensure you have your analytics platform of choice set up to track the key performance indicators relevant to your conversion journey. Set aside time to regularly review and, where necessary, deep dive into the metrics. Back in 2008, even Amazon wasn’t tracking conversion clicks but there’s no excuse not to harness the power of your data in 2024.

Do live user testing

Stats will tell you the What, but they can’t tell you the Why. They can tell you what customers do but can’t tell you how they feel. And while data analysis often requires big numbers to suggest trends, user interviews or usability testing can yield some results with even a small pool of participants so can represent excellent value for money. User testing is what gave Jared Spool and Amazon the insight they needed to devise their game-changing user flow.


A/B, split or multivariate testing is where you serve different versions of your website to cross sections of users to see which version performs best. Ideally you change one small thing at a time so you know exactly what has made the difference.

While there are some CX design decisions that we can make confidently based on industry best practices and heuristics, there are also many instances where the results will vary based on the brand, the product type, the user demographics... That is where ongoing conversion rate optimisation (CRO) is needed to unleash the full potential of your store.

ecom insights in the mail

Shopify's all-in-one platform provides a comprehensive set of tools to build, manage, scale and grow your ecommerce.
We promise not to spam you!
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.