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Increasing Delivery Saver Conversions

  • Comms optimisation,
  • Loyalty,
  • Membership,
  • Retention

Cowry Consulting
March 26, 2026 - 3 min read

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How behavioural science helped Tesco convert more free trial users into paying subscribers

The Challenge

Tesco’s Delivery Saver subscription helps customers save money on online grocery deliveries. While the service provided clear value to customers, Tesco identified an opportunity to increase the number of customers converting from free trials to paid subscriptions.

Three reminder emails were sent during the free trial period to encourage customers to sign up to the paid plan. However, conversion rates indicated that these communications were not performing as effectively as they could.

Tesco partnered with Cowry to understand how behavioural science could improve these communications. The challenge was:

How can behavioural design increase engagement with reminder emails and encourage more customers to convert to paid subscriptions?

Customers enjoyed Tesco’s Delivery Saver during the free trial, but many failed to convert simply because the value of the service wasn’t salient at the moment they needed to decide.

Our approach

Cowry conducted a behavioural analysis of the existing email communications to identify psychological barriers preventing customers from engaging with the content and taking action.

Behavioural audit – We reviewed the three reminder emails sent throughout the free trial period to identify behavioural friction points.

Friction analysis – The analysis revealed several issues affecting engagement, including dense text, unclear messaging and limited visual hierarchy, all of which made it harder for customers to process the information.

Behavioural design – Using these insights, we redesigned the emails to improve clarity, increase motivation and guide customers toward the subscription decision.

In total, eight behavioural interventions were introduced across the redesigned communications.

 

Behavioural insight

Our analysis identified several behavioural challenges affecting conversion.

 

 

 

1. Information Overload

What we observed
Customers were presented with large blocks of text and excessive information.

Why it happens
When communications require too much effort to read and understand, people disengage.

What it means
Emails must be visually simple and easy to scan so customers can quickly understand the value of the offer.

2. Delayed Decision-Making

What we observed
Customers often delayed making a decision about the subscription.

Why it happens
Without a clear sense of urgency, people postpone decisions until later, which often leads to inaction.

What it means
Communications should highlight the potential loss of benefits if customers fail to act.

3. Social Uncertainty

What we observed
Customers may be unsure whether the subscription is widely used or worthwhile.

Why it happens
People often look to the behaviour of others when making decisions.

What it means
Highlighting how other customers benefit from the service can increase confidence and motivation.

The solution

Cowry redesigned the three reminder emails using behavioural science to improve engagement and conversion.

Eight behavioural interventions were introduced across the redesigned communications.

Examples included:

  • Loss aversion – Emails emphasised the limited time remaining for customers to continue enjoying the benefits of Delivery Saver, increasing motivation to act before the trial expired.
  • Social norms – Messaging highlighted the savings other customers were achieving with Delivery Saver, reinforcing the idea that many shoppers were already benefiting from the subscription.
  • Salience – The visual layout was redesigned to improve readability and attention.

Clear hierarchy, stronger imagery and simplified content made the emails easier to process and more engaging.

 

Impact:

The behavioural redesign produced measurable improvements in subscription conversions. Following the success of the intervention, Tesco began implementing the optimised design principles across their wider suite of Delivery Saver communications. The programme is now informing best practice across future customer communications.

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increase in Delivery Saver sign-ups

 

“We believe in partnering with experts and Cowry has a proven methodology using cognitive and behavioural psychology that really works. Through our pilots we have already seen significant benefits across the business in how we support customers and make it easier for them to engage and make good decisions about their financial futures.”

Michael Reed-Smith
Retail Director, Standard Life

Why it worked

The intervention focused on how customers actually process communications rather than simply what information was provided. By simplifying content, increasing urgency and reinforcing social proof, the redesigned emails made the decision to subscribe clearer and more compelling.

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