Evidence use by parliamentary committees: what is it good for?
UK parliament image with "committees" written on it

By Marc Geddes

Select committees in the UK House of Commons are the principal mechanism by which Parliament holds government to account, which can be highly influential on government policy and legislation. While many adopt distinctive approaches and styles to undertake their scrutiny work, a key element of all committee work is the basis of their scrutiny through an evidence-gathering process. Many of us are familiar with oral evidence: combative sessions between chairs and ministers, emotional testimony from high-profile witnesses, or significant and detailed information-gathering with academics, NGOs, think tanks and businesses. Alongside these sessions, committees receive large volumes of written evidence from a whole host of groups and individuals to share their perspectives on a policy question under scrutiny. Evidence, then, is an everyday part of committee work. But how well is the process working? What are the practices of gathering and using evidence? That’s exactly what I wanted to find out in my 12-month parliamentary academic fellowship, organised by the Parliamentary Office for Science and Technology (POST).

In autumn 2021, I set out to review and study trends and practices of evidence use by committees. Although recent research has begun to shed light on the role of evidence in Parliament (especially POST’s own landmark report from 2017), I was intrigued to examine the everyday practices and judgements made by MPs and officials as they directly engage with, question and handle evidence. To study their views, I therefore undertook interviews with 50 participants (26 MPs and 24 officials) to reflect on the processes and practices for gathering, analysing and using select committee evidence. There are some unsurprising findings: written evidence makes up the bulk of evidence and is indeed seen as the main source of information for officials. MPs’ own engagement focuses on oral evidence, which are usually divided into information-gathering or accountability types of hearing.

Alongside these findings, I found three trends that are impacting the way that committees gather, analyse and use evidence. First, there is a much bigger focus on ‘lived experience’ as a form of evidence to support formal and informal evidence-gathering than in the past. Committee members, in particular, value direct engagement with the public and with those that come into direct contact with government policy. As a result, committees have sought to innovate with the use of social media to elicit questions, use of surveys to understand the public’s views of government policy, and focus groups to get more qualitative and in-depth knowledge.

Second, committees’ long-standing interest and tradition in gaining a diversity of political viewpoints is being matched by an emphasis of diversity on witnesses’ personal characteristics. Increasingly, committees see it as important to make sure that their evidence reflects the make-up of wider society.

Both of these factors come out of a third trend that I have observed, namely that the role of select committees is changing. Committees exist not only to provide scrutiny of government policy, but increasingly for MPs (and officials, though this was less noticeable) committees should be vehicles for public participation. This builds on previous initiatives and academic research on how to combat public disaffection with politics and political institutions.

The three trends – especially the final one – raise really interesting questions about the democratic and institutional design of parliaments. First, it raises a normative question about how far committees should pursue a role of public participation. Second, relatedly, it raises a practical question of how well committees are equipped to fulfil this, and other, roles.  These are important questions because I have found, in my research, several challenges that the changing trends and patterns seem to give rise to: a significant growth in the volumes of evidence, which has created pressures on committee teams; a lack of clarity over the principles and values of using ‘lived experience’ as a form of evidence in committee inquiries; a continuing tension in promoting diversity of evidence, which some see as a normative good but others do not; and resultant pressures on resources, including time, training and staff to fulfil the growing number of tasks being given to committees. At the same time, the process for gathering evidence has remained largely the same – despite innovations, improved technological advances, and changing practices and values.

Based on my research, and interviewees’ reflections, there are lots of ways that evidence-gathering could be improved (in my report, I list 14 small suggestions), but there are two areas I want to focus on. First, we need to open a debate about what ‘good’ evidence use in Parliament looks like. These choices are not without consequences. And while I can sketch out broad principles – appropriateness, diversity and representativeness, systematic analysis, and focused on the needs of MPs – much more work could be done about what values parliamentary democracies need to hold to promote use of evidence.

Second, regarding the procedures of evidence-gathering, I want to suggest that maybe the traditional process for gathering evidence – that will be familiar to an MP from today as much as it would for one in the nineteenth century – needs updating. I would re-think evidence in terms of ‘pillars’, each recognised formally as evidence in Parliament:

  • Pillar 1. Submissions of information/evidence. Formerly known as written evidence, this would include other formats except Word or PDF documents written by professionals, such as video evidence, pictures, graphs, etc.
  • Pillar 2. Committee hearings. Formerly known as oral evidence, this part of the process would be kept largely the same but with a plainer form of language.
  • Pillar 3. Consultation and engagement. Rather than classing all non-written/oral evidence as ‘informal’, I would give other processes for gathering information a formal status through a summary document within Pillar 3, which summarises the findings from surveys, focus groups, or large volumes of written evidence received by individuals.

I am aware that this suggestion is not without its own problems – but once again I want to open a debate to question whether the way that the process currently works is working well in light of the changing practices of evidence use by Parliament.

This gives you a flavour of some of the findings and conclusions from my research project. You can find the full report on which this blog is based here. I am hugely grateful to have had the support from Parliament to pursue this research, and time and funding from my university to pursue it. Most of all, my interview participants have been incredibly kind in giving up their time for this research.


Dr Marc Geddes is Senior Lecturer in Politics at the School of Social and Political Science, University of Edinburgh. His research focuses on how MPs and officials interpret and undertake their roles in parliaments. He has published widely on the role of select committees in the UK House of Commons, including an award-winning book, Dramas at Westminster (Manchester University Press, 2020), and in a range of specialist journals and for public audiences.


Featured image from the UK Parliament Website