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GSS > Guidance > Harmonisation


Harmonisation is about making statistics more comparable, consistent and coherent. It improves efficiency and enables users to draw more value from statistics. To improve harmonisation, analysts, researchers and data owners should aim to, where appropriate:

  • use consistent definitions and survey questions in data collection
  • improve understanding of how data and statistics can be integrated and used in combination
  • present statistics in a comparable and coherent way

But, since statistics producers will each have their own specific user requirements, this is not always appropriate. In these cases, they should consider other actions to improve the coherence of their data and statistics, such as providing improved guidance.

What support is available?

We have developed a two year GSS Harmonisation Strategy.

This strategy sets direction on the coherence and comparability of statistics across the GSS. It was developed through consultation with key stakeholders across the GSS and sets out realistic actions to improve comparability and coherence across official statistics. The strategy will provide guidance for all those involved in delivering statistics across the GSS.

Harmonised principles are guidance on how to make statistics more comparable by encouraging producers to use the same methods of data collection and presentation. The principles include definitions, survey questions, standards for administrative data, rules for presentation and guidance for users.

Producers of statistics can use harmonised principles to improve harmonisation when they collect and publish statistics on a given topic.

Users can use the principles to improve their understanding of how to compare and combine statistics when appropriate.

Browse the harmonised principles by topic.

Search all the harmonised principles.

Harmonisation champions work across the GSS to increase awareness of harmonisation and the help available.

Read more about the harmonisation champions network.

If a department needs help with harmonisation, the harmonisation team (based in the Office for National Statistics but here to help the whole Government Statistical Service) are happy to collaborate closely.

Email to find out more.

This guide will provide answers to our frequently asked questions and give an overview of what the GSS harmonisation team do.

Why is harmonisation important?

Harmonisation allows analysts to work together to gain deeper insight from their data. This delivers more meaningful statistics that give users a greater level of understanding.

Bringing experts together can also take advantage of shared knowledge across the system. This means we can develop ways to best capture data and produce Official Statistics that answer user questions. It can also achieve cost savings by realising efficiencies of avoiding duplication.

Harmonisation is also required to follow the Code of Practice for Statistics.


Who are the GSS harmonisation team?

The GSS harmonisation team are a team of researchers and statisticians within the Best Practice and Impact (BPI) division. The team works on a cross-governmental programme of work to support the GSS by improving harmonisation. Our aim is to provide clearer and more robust comparison between data sources.


What is the GSS harmonisation champions network?

The harmonisation champions network works across the GSS to:

  • increase awareness of harmonisation
  • promote the help and support that is available

Each government department has a nominated harmonisation champion (or several champions).


What is a harmonised principle?

Harmonised principles are guidance on how to make statistics more comparable. They should encourage producers to use the same methods of data collection and presentation. The principles can include:

  • definitions
  • survey questions
  • standards for administrative data
  • rules for presentation
  • guidance for users


What is a harmonisation topic?

Harmonisation topics are related themes under which harmonised guidance and principles are grouped e.g. health, housing, demographics.


Contact us

For general questions about harmonisation, please email

For questions about a specific harmonised principle please find the relevant contact on the principle of interest.

If you want to find out more about what harmonisation means for your department, speak to your harmonisation champion.