How Plain Numbers nearly tripled customer understanding for Cadent

The challenge:

Cadent, the UK’s largest gas distribution network - bringing gas to 11 million homes and businesses, wanted to improve accessibility of their literature, specifically their payment documents for new connection customers.

What we did:

We partnered with research specialists Thinks Insight to run a rigorous randomised controlled trial with over 1,000 UK participants.

Half saw Cadent’s original communication, while the other half saw the version where the Plain Numbers Method had been applied.

We then tested what people actually understood through five comprehension questions.

(click on the image to enlarge)

Before (click on the image to view the detail)

After (click on the image to view the detail)

The results: the Plain Numbers Method significantly improves understanding.

Understanding nearly tripled – the proportion of people who correctly answered at least 4 out of 5 comprehension questions jumped from 20% to 56%
Biggest impact on cost understanding – the most dramatic improvement was in understanding total costs – rising from just 3% to 60% of customers getting this right.
Better customer sentiment – customers who saw the Plain Numbers version were:
More satisfied with the information provided (71% vs 79%)
More positive about Cadent as a company (57% vs 65%)
Supporting vulnerable customers – the Plain Numbers Method had the greatest impact on people with lower number understanding. Only 10% of these people got 4 or 5 answers right on the original, this jumped to 38% in the Plain Numbers version.

The gap between perception and reality

One of the most striking findings: while 79-83% of people thought both versions were ‘clear, fair and easy to understand’, actual comprehension, 20% on the control and 56% on the Plain Numbers version, told a very different story.

This shows why testing real understanding – not just asking people if they think something is clear – is so important.

“Understanding important documents, like bills and safety advice, should not be a test. They should be simple and accessible to everyone, regardless of comprehension level.

We already offer our documentation in alternative formats and languages to cater to our customers’ needs, so trialling the Plain Numbers Method was a natural next step in making our communications even more accessible.”

— Phil Burrows, Head of Customer Vulnerability at Cadent

Read our research with ClearScore into communicating APR here

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Initial trials (5 separate pieces of research)

In 2021, with the support of the Bank of England and Kantar Public, we conducted a series of randomised controlled trials to test just how effective the Plain Numbers Method could be.

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Plain Numbers in Practice report

In July 2024 we published our Plain Numbers in Practice report, highlighting the diverse applications of the Plain Numbers Approach across a wide range of communications.

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Case Studies

See how Plain Numbers improves customer understanding with real-world case studies.

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