PPI is when patients, carers and members of the public are actively involved in research. This can include patients, carers and members of the public working together with researchers at all stages of the research cycle to:

• select research that is important and relevant to the public
• design and deliver projects
• develop understandable information sheets for people taking part in research
• carry out some aspects of the research (for example interviews)
• interpret the results of the research
• make sure the research is reported in understandable ways and that good research is heard about

Involvement can help develop research that responds better to the needs and interests of patients, carers and researchers than that developed by researchers alone. Researchers may not have first-hand experience of the illness they are researching and patient and carer involvement can provide them with important insights.