We collect data to better understand how defendants in the criminal justice system decide to plead guilty. People tend to think that defendants only plead guilty when they are guilty, but research shows that actually some people plead guilty when they are unsure whether they have committed an offence or even when they know that they are innocent. It is therefore very important to understand when and why defendants are pleading guilty.

If you are a defendant who has pled guilty when innocent and would like to share your experiences with us, please get in touch.

Below is some of our existing data on guilty plea decision making.

For our publications on guilty pleas, visit our publications page.

Anchor: adults

Guilty Pleas in Adults


Our work examining guilty plea decision-making in adults has shown that many factors other than factual guilt can lead or even pressure defendants to plead guilty. These include the ability to avoid custody by pleading guilty where a custodial sentence could be imposed at trial, the time and money involved in a full trial, and the ability to obtain charge discounts.

Pressures to plead guilty

In the video below, our lab director, Dr Rebecca Helm, joins Dr Ed Johnston, Karl Turner MP and Jerry Buting to discuss the guilty plea system and pressures that defendants face to plead guilty.

The pressures defendants can face to plead guilty regardless of guilt have been highlighted by the recent Post Office Scandal, and have been discussed by Dr Helm in this context in a recent blog post. Dr Helm has also published articles discussing pressures to plead in both the USA (see here) and England and Wales (see here and here).

Why do adults plead guilty?

We work with legal professionals to better understand why adults plead guilty.

The data below is taken from a pilot study where we asked around 20 lawyers what they think is important to adult defendants when deciding whether to plead guilty.

Our research suggests that the factors that are important to defendants is likely to vary based on their circumstances. For some defendants, pleading guilty can ensure the avoidance of a custodial sentence which may be imposed at trial. For others, the time, cost, and stress of trial may be prohibitive and they might plead guilty to avoid trial. These factors have the potential to disproportionately influence the decisions of defendants from certain groups, for example single parents or those with precarious employment. There may be implications of this disproportionate influence in England & Wales under the Equality Act 2010.

false guilty pleas

As a result of pressures to plead and the variety of considerations that can be important to defendants making plea decisions, innocent defendants do plead guilty. Our work seeks to understand why innocent people plead guilty and how changes to legal procedure can minimise miscarriages of justice arising from guilty pleas, and also to help people who have pleaded guilty when innocent.

Generally, our survey results suggest that a non-trivial proportion of defendants who plead guilty are or may be innocent. The graph below shows data from one study in which we interviewed 90 legal professionals, and asked them to estimate the proportion of defendants who plead guilty but are actually innocent.

The Post Office Scandal

In the recent Post Office Scandal, many innocent people pleaded guilty to crimes they did not commit. We are conducting research to understand why they did so. For our initial summary of guilty pleas and incentives to plead guilty in the cases, please see the spreadsheet below:

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Key stats

of defendants pled guilty in the Crown Court in January – March 2021

weeks additional waiting time (when compared to median) for those who entered a not guilty plea in January – March 2021

of defendants prosecuted by the CPS pled guilty at first hearing in Magistrates Court in 2020

Anchor: children

Guilty Pleas in Children


Children are particularly vulnerable in guilty plea systems due to immature decision-making systems, over-responsiveness to short term benefits, and susceptibility to pressure. We have recently published two reports on these vulnerabilities, and the additional protections that children require when deciding whether to plead guilty:

Pressures to plead guilty

Our research with children who have pleaded guilty, and lawyers who work with children, suggests that children are particularly susceptible to pressures to plead guilty, which may lead them to plead guilty when innocent. Some of these pressures are discussed in the short video below.

Dr Helm has written about the particular pressures children face when deciding whether to plead guilty (see here), and also the psychological mechanisms that make children particularly vulnerable to pleading when innocent (see here).

Why do Children plead guilty?

We collect data to understand why children choose to plead guilty.

The data below is taken from a pilot study where we asked around 20 lawyers what they think is important to child defendants when deciding whether to plead guilty. Note the differences between this data and the comparable data for adults, presented above.

The data presented above is supported by other data we have gathered from larger samples that suggests that legal advice and sentence discounts may be influencing child defendants more than adult defendants.

Risks of false guilty pleas

As noted above, children are at particular risk of pleading guilty when innocent as a result of the influence that pressures to plead guilty have on them. In our recent survey of 33 lawyers, we asked lawyers to estimate the proportion of children pleading guilty who they thought were actually innocent. There was wide variation in estimates, and the overall average estimate was that 15% of children who plead guilty are actually innocent (see here for a Daily Telegraph report on this work).

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Key stats

of children appearing at the Crown Court in 2019 pleaded guilty

of children appearing at the Magistrates’ Court in 2019 pleaded guilty at their first appearance

Approximately 15%
of children who plead guilty are innocent, according to our recent survey with lawyers.

Research Project briefing:

Incentivised Admissions in Children

Anchor: decision-making

Guilty Plea Decision making


Work in cognitive and social psychology can help us understand when and why defendants are likely to plead guilty, and the conditions under which defendants are likely to plead guilty even when innocent. Below are some existing research papers which have utilised a variety of approaches to understand guilty plea decision-making. The majority of these papers are based on the US plea bargaining system, but we also conduct work examining guilty plea decision making in the system in England & Wales.

Our work focuses on plea systems in England and Wales and the USA and is based on psychological theory and quantitative data analyses. These analyses can help inform legal procedure that will maximise guilty pleas from guilty defendants and minimize guilty pleas from innocent defendants. The analyses can also help identify conditions under which defendants who are innocent would be likely to have pled guilty.


Our existing work suggests children and a certain sub-group of adults are more prone to pleading guilty to crimes that they did not commit and making decisions that do not reflect underlying values (see Helm & Reyna 2017 and Helm, Reyna, Franz, & Novick, 2018).

Computational Modelling

Dr. Helm is currently a co-investigator on an American Psychology and Law Society funded project using computational modelling to advance our understanding of guilty plea decision-making. A long-term goal of this work is to generate policy recommendations that will maintain a high rate of guilty pleas among the factually guilty, while preserving defendant autonomy and minimising the risk that innocent defendants will plead guilty. The project is in collaboration with Dr. Tina Zottoli, Dr. Vanessa Edkins, Dr. Michael King, and Dr. Michael Bixter.

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Anchor: cautions



Guilty pleas are not the only type of incentivised admission. In some cases, people who may otherwise be proceeded against in court can have their case dealt with via a caution (a type of formal warning) but only if they are willing to admit guilt.

The ability to avoid formal prosecution and only receive a caution only if guilt is admitted has the potential to pressure both guilty and innocent defendants to admit guilt.

Cautions in Children

Our research suggests that children may be particularly susceptible to admitting guilt and accepting a caution, even when not guilty. For more detail on our work on cautions in children, see our reports below:

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Key stats

children cautioned between April 2019 and March 2020

of appropriate adults we interviewed believed innocent children accept cautions

of lawyers we interviewed believed innocent children accept cautions