The primary aim of this study was to identify the factors that researchers perceive as influential in the recruitment of participants to their clinically focused research. Infrastructure, the nature of the research, recruiter characteristics and participant characteristics were all deemed important. The first three themes are, in theory, more amenable to modification than the last, for example through the development of systems to improve identification and access to eligible participants
, designing studies with reduced participant burden
 and ensuring that recruiters have the appropriate knowledge and skills
. The discussion of participant characteristics focused on the concept that certain patients were thought more likely to agree to research participation than others. The danger with such an observation is the potential for recruiters to stereotype potential participants based on previous experiences, and therefore choose not to approach individuals who are otherwise eligible. As the NHS constitution pledges to inform all patients of research studies that are relevant to them and in which they may be eligible to participate
, recruiters must be aware of the potential to deviate from this duty. In reality, the decision to participate in clinically focused research is frequently multifaceted and requires potential participants to consider the personal pros and cons of taking part at any given time
. The research nurses interviewed for the current study raised this point and explained their attempts to approach all eligible patients, regardless of any preconceptions about whether or not they would agree to participate.
The general perception that doctors are more successful at recruiting research participants than nurses has been explored previously. Donovan et al.
 found no significant difference in recruitment rates between urology consultants and nurses for a prostate cancer RCT and calculated that nurses were more cost-effective recruiters, despite spending longer on average with each patient. In the current study, recruitment was viewed more as a team effort. Having the doctor mention research participation as part of the routine consultation was thought to be beneficial, as was having integrated clinical and academic teams on site. However, these strategies require sufficient staffing and resources and rely on specific funding for research posts
. The possible recruitment benefits of having an established therapeutic relationship with potential study participants
, sharing similar cultural backgrounds or languages
, and employing peer recruiters
[24, 25] have all been explored in the literature. However, the influence of the recruiter-participant relationship was not widely discussed by the interviewees, nor were the subjects of culture and ethnicity. There was a general consensus that recruiters adopted the same recruitment strategies for all demographic groups, but observational investigations of recruitment practices would be beneficial to further explore these issues. The use of eligibility criteria that include only those who speak sufficient English was attributed to a lack of resources available for interpreter services. Resource limitations would also restrict the use of peer recruitment programmes or other strategies aimed at including minority groups. As recruiting a representative sample is essential for the generalisability of research findings
, additional investigation of this issue is required.
The research scientists interviewed were disappointed that they were no longer permitted to discuss their study directly with potential participants. This finding echoes the views of biomedical research scientists involved in placental perfusion studies
. The scientists raised legitimate concerns that the individuals involved in recruitment did not have sufficient knowledge of the intricacies of the study to be able to fully explain the background and rationale to potential participants, or to answer questions about particular methodologies
. It in current study, it was local, rather than national, policy that dictated the exclusion of research scientists from recruitment activities. The potential benefits of allowing research scientists to recruit participants to their research include reducing the workload for clinicians, providing expert knowledge of the study processes and rationale, and separating research recruitment from routine clinical care. The potential drawbacks include the research scientist having a vested interest in the research without the balance of coexisting clinical duties, and the absence of a previous therapeutic relationship with the patient. Further exploration of this issue is required, however it may be advantageous to consider including clinical research scientists as part of the recruitment team, with safeguards to guarantee that patients are not exploited.
The recommendation to use an opt-out system, where patients are required to contact the research team if they do not wish to be invited to participate in clinical research, was made in a recent systematic review
. Several interviewees suggested that this might be a beneficial system, however this strategy is not currently employed, and further work is required to pilot the use of opt-out within these settings. A variation of this strategy, where patients are invited to opt-in to the anonymous donation of surplus tissue after clinical tests, was also discussed. This type of tissue biobanking is available at the interviewees’ hospital sites for patients with a diagnosis of cancer, but is not routinely adopted in other clinical areas. Further research into the extension of biobanks to include other clinical specialties appears warranted
The use of open, rather than blinded trial designs, and telephone reminders were also recommended by Treweek et al.
. There is debate over the utility of open study designs due to the potential for increased bias
, but this methodology is gaining support
. The interviewees used modified versions of this strategy, such as having an open or crossover phase after the main trial, and believed this was beneficial for recruitment. None of the interviewees specifically discussed the use of telephone reminders.
The recruitment strategies employed by the interviewees were similar to those identified in our recent meta-synthesis, although there was less focus on emphasising the benefits of research participation in the current study
. In addition to the possible coercive aspect of emphasising the benefits, the interviewees believed that altruism was the key reason for patients accepting the invitation to participate, and therefore strategies based on highlighting potential personal benefits would not sit with this premise. The dominance of practical issues as proposed reasons for patients declining the invitation to participate in research have been documented elsewhere
The key factors associated with conducting clinically focused research in London were language and travel time. Interviewees were unable to offer interpretation services to facilitate discussions about research with patients who did not speak sufficient English. The most recent government data shows that within the associated South London boroughs between 19.6-20.3% of residents do not speak English as their primary language, compared with 15.3% and 7.1% in the next biggest UK cities Birmingham and Leeds, respectively
. The range of primary languages spoken is also greater in the interviewees’ regions, with more than 54 different languages, compared to 36 in Birmingham and 29 in Leeds
. Traditionally, individuals from ethnic minorities have been considered less likely to participate in clinically focused research, however studies from the USA suggest that this is not the case and recommend that more needs to be done to ensure access to research for minority groups, rather than interventions aimed at increasing willingness
[32–34]. Strategies to aid the removal of language barriers identified in the current study would improve access to research and could potentially increase recruitment, however further investigation is required.
The interviewees also observed that patients with long travel times to the hospital were less willing to take part in research. When designing clinically focused studies, it may therefore be useful to explore the interviewees’ suggestions of increasing the use of information technology for data collection and forming collaborations with local healthcare services to minimise participant travel. As the average commuting time is 48% longer in London than elsewhere in the country
 this factor may be less problematic in other locations, however most tertiary and quaternary healthcare services conducting research are likely to experience similar travel issues.
Strengths and limitations
The current study adds to previous work by providing experiential reports and perceptions from research teams in three different non-cancer outpatient settings, within a specified geographical location. However, as the research teams involved were based in South London, further work is required to ascertain whether these findings translate to other regions, nationally and internationally.
Although interviewing was continued until saturation, the small sample size in the current study means it is not possible to infer any differences between the experiences and opinions of the different professions within the research teams. Furthermore, the current study relied on information collected from semi-structured interviews, and may have been subject to reporter bias. Attempts were made to minimise the degree of bias by selecting independent research teams and interviewing participants individually. Additional explorations of the researchers’ practices that include observation of the recruitment situation would be beneficial, but were beyond the scope of the current study.