Dear Ian

Assessment of statistics about butterflies, England and UK

We have completed our assessment of statistics from the Butterflies in England and Butterflies in the United Kingdom publications produced by Defra. I am grateful for the positive contribution and engagement from your team throughout the assessment process.

Our assessment found that the statistics are valued by a range of users across policy areas, academia, and research, and form part of the suite of Biodiversity Indicators where they are considered to give a good indication of the broader state of the environment. Both sets of statistics are based entirely on data drawn from the UK Butterfly Monitoring Scheme (UKBMS) which is an excellent example of citizen science where a large and detailed data set is gathered by volunteers. This means that a key biodiversity measure is based on a much larger and more-varied sample than might be the case for a more conventional survey.

We have identified several ways that the statistics should be strengthened further to improve the overall quality and value of them. Our recommendations focus on the communication of methods and decisions made round long terms trends as well as formalising and publishing information on developments and engagement with users.

We judge that the statistics from the two butterfly publications can be designated as National Statistics once we have confirmed that the requirements set out in the report have been met. Addressing the requirements will demonstrate that your statistics meet the highest standards of trustworthiness, quality and public value and comply with the Code of Practice for Statistics.

I am copying this letter to Lindsey Clothier, Deputy Head of Profession for Statistics at Defra, and to the team at Defra – Clare Betts, Simon Hatfield, Karen Thomas and Madeleine May.

Yours sincerely


Ed Humpherson

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