Evidence types

The YJ Resource Hub Evidence Library contains three main types of evidence:

Research

Original studies which use methods like interviews, surveys, and data analysis to explore youth justice issues.

Evaluation

Assessments of interventions and programmes to understand how they have been implemented and their effectiveness.

Evidence review

Concise reviews of existing research, providing key findings and practical insights for policy and practice.

Research methods

Research studies hosted on the resource hub tend to utilise one or more of the following research methods:

Qualitative research methods involve collecting and analysing non-numerical data, such as interviews and observations, to understand people’s experiences and perspectives.

Quantitative research methods involve collecting and analysing numerical data to identify patterns and test hypotheses, often using tools like surveys, questionnaires, and experiments. For example, researchers might distribute a survey to gather data on children’s attitudes towards education.

Mixed methods research combines both qualitative and quantitative approaches to provide a comprehensive understanding of a research problem, often using tools like interviews, surveys, and experiments. For example, a study might use interviews to explore personal experiences and surveys to gather numerical data on the same topic.

Participatory research methods involve collaborating with participants throughout the research process to ensure their perspectives and experiences shape the study, often using tools like focus groups, community meetings, and collaborative workshops. For example, researchers might work with a community to identify local health issues and develop solutions together.

Ethnographic research methods involve immersing oneself in a community or culture to observe and understand their daily lives and practices, often using tools like participant observation, field notes, and in-depth interviews. For example, a researcher embed themselves in a local authority to understand power structures and social interactions.

Case file analysis in youth justice involves reviewing detailed records of individual cases to understand patterns and outcomes, often using tools like case notes, court documents, and reports. For example, researchers might examine case files to identify common factors in youth offending and the effectiveness of different interventions

Evaluation design

Evaluations hosted on the resource hub tend to utilise one or more of the following research methods:

A study where people are randomly assigned to two or more groups, one receiving the intervention being tested, the other (the comparison or control group) has an alternative intervention or no intervention at all.

A study where the comparison group has not been created at random. Statistical techniques are used to allow outcomes between two groups to be compared even where there may be differences between the characteristics of those groups. This gives an indication of whether an intervention has been effective. Common examples include Regression Discontinuity Design, Interrupted Time Series, Difference in Differences and Propensity Score Matching

Measuring outcomes before and after intervention. Either with no comparison group or a non-matched comparison group e.g. children who don’t take part in the programme may have different characteristics to the children who do take part in the programme meaning any differences in their outcomes may not be due to the programme.

Perceived outcomes are measured through qualitative data collection methods.

A way to draw conclusions about a programme’s effectiveness in the absence of any comparison group. This usually involves establishing a theory of change and collecting evidence to understand whether a programme is working the way it is expected to, including how and why it worked.

Evaluation to understand how the programme was delivered and implemented, how it was experienced by users, as well as what worked well and not so well

Bringing together findings from an umber of different studies on the same subject. Common examples include meta-analysis, systematic review and rapid evidence assessments.

Evaluation outcomes

Does It Work?

Untested, new or innovative: Where no formal evaluation or only process evaluation has been used

Promising: Where qualitative outcome evaluation, pre-post or theory-based evaluation has been used, and some benefit or potential benefit identified.

Effective for one or more outcomes: Where a Randomised Control Trial or Quasi-Experimental Design has been used and beneficial effects identified.

Not effective for any outcomes measured: Where any outcome or impact evaluation design has been used and findings show no benefit.

Harmful: Outcomes measured show detrimental effects to children.