Sampling for PSV Interviews

Interviews with PSVs adopted a stratified sampling approach with specific volunteer characteristics used to inform selection decisions. Findings from the online survey conducted as part of this study were influential in the PSV sampling process, with interviews presenting an opportunity to both gather the views of volunteers underrepresented in the survey compared to the MPS as a whole (in particular younger volunteers, and those with fewer years’ service), and explore themes highlighted in survey data in more depth. A sequential mixed method data collection strategy such as this supports an iterative approach to data collection, where data

collected in one phase contributes to collection in the next. This allows the researcher to gather data that builds upon findings in the earlier phase and to select participants that enable this (Driscoll et al., 2007).

Interviews were sought across three PSV role types identified in the survey to explore potentially different motivations, contributions and experiences: administration;

community engagement or customer focused roles (e.g., front counter/reception services, quality of service calls to victims); and roles with a more operational focus (e.g., cadet leaders, CCTV Visual Images Identification and Detection Office). Volume of interviews was weighted further towards the latter two (a target of eight interviews in each role type), rather than administration (four interviews), which was fairly well represented within the survey. Interview sampling also attempted to address the under representation of younger volunteers (under 54 years of age) and those who had volunteered for less than a year in the survey, compared to the MPS PSV cohort as a whole.

In terms of sampling frames and selection methods, three options were available, with aspects of each – together with an additional snowball sampling method, which presented itself as the fieldwork progressed – incorporated in to the study:

• PSV survey respondents: Just under half (42%, n=59/140) of survey respondents stated that they were happy to take part in an interview and provided their contact details. Approximately 17 individuals were ‘long listed’

as potential interviewees, on the basis of their role, age, and length of time volunteering, with seven ‘short listed’ for initial contact. As they had consented to sharing their personal details, these PSVs were contacted directly, with an introduction to the researcher, the study, and details of what their participation would entail (see Appendix G). Five interviewees were recruited via this method.

• Random selection within Metropolitan Police Service HR records: Although not available directly to the researcher in ‘raw form’, the MPS provided a sanitised,

non-personalised version of HR data detailing individual PSVs, their role, borough of volunteering, and length of time as a PSV. This information was used to identify suitable interviewees (based on role type, age, and length of volunteering service) and carry out random selection (using an online random number generator tool) in order to select individual record identifiers, which were then passed to the Metropolitan Police Volunteer Programme Manager to be matched to personalised PSV data. In cases where the identified PSV was unsuitable – usually due to target age profile or ‘inactive’ volunteer status – the nearest record that met the same criteria was selected and so on, thus retaining the randomised nature of the method. Invitations to these PSVs were made via their borough volunteer manager who contacted them with full details of the study and secured their consent to pass their email address on to the researchers. Three interviewees were recruited via this method.

• Targeted selection via the Metropolitan Police Volunteer Programme Manager: A targeted approach was taken to identify PSVs that performed more distinct or unique (usually operational) volunteering roles, as these were not obvious in HR data therefore could not be randomly selected. Contact with these PSVs was again made via the borough volunteer manager as above. Eight interviewees were recruited via this method.

• Snowballing: Four interviewees were recruited through a snowball sampling method – two via a PSV interviewee, and two who expressed an interest in the study during a police station visit to interview a volunteer manager. This was unexpected; however, as two presented demographics of interest (i.e., younger volunteers) and the other two occupied roles that were, at the time, still lacking in the interview sample (i.e., administration) it was decided to capitalise on these opportunities. As Kemper et al. (2003) assert, sampling for social research sometimes forces pragmatic choices such as these.

Each of the sampling approaches posed limitations: interviewing survey respondents essentially presented a ‘double dose’ of self-selection (i.e., volunteers chose to respond to the survey and then chose whether or not to provide their contact details);

unique volunteer stories amongst those not selected; while recruiting via the Met Police Volunteer Programme Manager was open to ‘cherry picking’ to reflect a chosen viewpoint. Combining elements of each approach went some way to negating limitations; however, it was important to acknowledge these caveats throughout fieldwork and analysis.

The ‘administration’ of arranging interviews – contacting potential participants, introducing the study to them, securing consent, and negotiating a time and place for the interview to take place – was an ongoing process, starting in January 2017. An initial invitation was sent to selected PSVs with a follow up ‘chaser’ email approximately two weeks later. A small number of initially selected PSVs did not reply to the invitation. As Crowhurst (2013) argues, being granted access to potential research participants by a gatekeeper (in this study, the Met Police Volunteer Programme Manager) does not exclude negotiations at other stages of the research.

Indeed, access is an ongoing practice with the potential respondent the ultimate

‘decider’ of whether they take part or not. These ‘gaps’ in the sample were serendipitously filled (as is sometimes the case in social research) by the snowballing opportunities outlined earlier.