For instance, male suicide rates are three times that of female suicides in the UK; however, in studies which compare self-reported mental health outcomes in the UK, females commonly report worse outcomes. Whilst this is often attributed to differences in response tendency, a simpler possible explanation is that the types of people experiencing psychiatric distress are very unlikely to participate in such studies. This mixed methods project will explore the plausibility that this disconnect is caused by such selection bias and develop an intervention to improve understanding amongst research participants of the consequences of non-random participation.