Thames Water: Customer bill | Trials

We recruited 1,000 participants representative of the UK population for this trial. 500 people saw an existing communication and 500 saw the Plain Numbers version.

The Plain Numbers version sought to communicate the same information in a way that was clearer and easier to understand.

We asked 5 comprehension questions to really prove whether customers understood the communication. We considered someone being able to answer 4 of these questions correctly an example of good understanding.

In this trial questions to participants included:
‘How much water have you used in the first half of the year?‘ and ‘What is the total cost for the water used in the first half of the year?’

Research results:

13%

Original version, answering at least 4 questions correctly

Research results:

48%

Plain numbers version, answering at least 4 questions correctly

The Plain Numbers Method in action

Numbers themselves
Combined the quarterly charges, removed the 4 decimal places and moved the calculations to the sidebar along with a link to read finer detail.

Numbers in context
Talking ‘human to human’ and making the numbers relatable by providing context and comparators.

How we think
No decisions are needed but seeking active engagement so introduced clearer headings to support ‘fast’ / System 1 thinking.

Full research results for Thames Water

Back to proof it works

Initial trials: Clearscore

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We recruited 1,000 participants representative of the UK population for this trial. 500 people saw an existing communication and 500 saw the Plain Numbers version.

13%

48%

The Plain Numbers Method in action

Numbers shape what people understand, how they make decisions, and who they trust