by aiming that 25 per cent of all interviews should be undertaken with participants living in Wales, Scotland or Northern Ireland. These methods adopted for sampling aim to increase the robustness of the research by enhancing the reliability and the validity of the data and in turn provide a greater understanding of stateless persons. The diversity of gatekeepers, multiple starting points for snowballing and the setting of flexible sampling quotas were all used to try to increase the diversity of participants. 1.3.3 Data collection Semi-structured interviews with stateless persons The researchers conducted extensive research in order to compile a database of over 400 gatekeepers to approach for the referral of participants. This database encompassed a variety of both voluntary and public sector bodies enabling a wide range of “starting points” for snowballing. The database included: refugee community organisations; crisis groups; detainee support groups; NGOs/refugee-assisting organisations; small local community groups and centres; university and student groups; online social networking websites; service providers such as housing associations and local councils; citizens advice bureaux and law centres; public bodies such as strategic migration partnerships. A referral form was designed which described the research and requested the referral of stateless or “unreturnable” individuals. It included a short questionnaire intended to help gatekeepers to identify the target population well as to enable researchers to “filter” the most appropriate participants referred. The referral form was distributed to the project contact database by email and post, and placed as a link on the Asylum Aid and UNHCR UK website. It was also featured in other organisations’ newsletters and mailing lists, as well as being distributed on relevant email lists, such as the Refugee Legal Group.24 Meetings and other follow-up work took place with organisations on the database about how best to encourage and facilitate participation in the research. These included Detention Action, Coventry Peace House, the Immigration Law Practitioners’ Association, Refugee Action, the British Refugee Council and the British Red Cross. Several of these organisations agreed for a researcher to present the project at frontline staff or management team meetings in order to increase awareness of the research, as well as to help ensure endorsement by senior members of staff and their engagement to encourage participation. This approach meant it was possible to secure large numbers of referrals despite the challenges inherent in trying to engage the participation of this type of hidden population. If the status or circumstance of the potential interviewee was unclear following receipt of completed questionnaires from individuals or organisations, a short call would be made to ensure that the potential participant’s circumstances were within the scope of the research. Participants for interview were selected to try to obtain a broad as possible sample. A semi-structured interview questionnaire was designed to capture comparable information identified as relevant for the research. The interview questions were a combination of legal and sociological questioning and were grouped around four key themes including reasons for statelessness or unreturnability, immigration history since entering the UK (if relevant), living conditions while in the UK and finally about statelessness and the individual. All interviews were digitally recorded. Detailed notes were taken, including the interview context, access 24 The Refugee Legal Group is an email group consisting mainly of legal representatives who provide advice to asylum-seekers. in the United Kingdom 19