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HMRC internal manual

Compliance Handbook

The One to Many Approach: planning a one to many approach: how will you measure the impact?

At the start of your planning, you need to consider how you will measure the impact. There is no point carrying out an OTM approach if you will not be able to tell whether it has succeeded or not.

KAI will be able to support you in analysing the outcome of your OTM approach. You will need to apply for KAI resource and you should do this early in developing your approach. See CH600280 for contact details.

A dedicated KAI resource will be allocated to work with you. KAI will help you to ensure your approach’s impact can be measured. They will help you to understand the data you will need to enable effective analysis.

You will need to take into account the following before you start an OTM approach to ensure you can measure its impact:

  • your population must be large enough for your findings to be statistically significant. This means that you have looked at enough people to be able to assume that your findings will apply to a wider population
  • the group must share a behaviour even if they may have different reasons for the behaviour. You are trying an approach that you think is likely to work with as many of the group as possible
  • you must compare it against control groups. They undergo the same day-to-day conditions as the target groups but are not exposed to the OTM approach. Any behaviour change observed in the target group can be compared with that of the control group, to identify how much of the change has been caused by the OTM approach and how much by other factors
  • you must understand what your success factors will be - see below.


Examples of relevant success factors may be:

  • increase in profit
  • increase in tax paid
  • expenses reduced
  • the customer’s behaviour has changed – will any action the customer takes be classed as a change in behaviour?
  • increase in registrations
  • a customer amends a return
  • the customer has filed on time due to the approach.