Sponsor Impact report low-incidence patient group comprising 50 individuals across the US, where budget constraints might limit the research to just two US markets. In such a scenario, finding 25 niche or lowincidence patients in a single market could pose a significant challenge, whereas spreading the eort across five markets could prove more feasible, says Hammock. Reaching niche and seldom-heard audiences usually requires extra eort, and often highlights some of the extremes found in our society. But the process is aided by considering the needs of participants first and foremost, thinking creatively, and taking the time to truly understand how best to engage. Accessing seldom-heard populations Whether it is because of vulnerability or their living situation, or simply a lack of desire to participate, there are eldwork agency to develop a strategy. It goes without saying that many reasons why some people are relevancy and incentivisation matter. that the population of interest may and timely most people have a seldom heard in research. It may be not wish to disclose they are members of a specic group perhaps because their behaviour is illegal; or it may be that an investigation of a group with relatively low numbers is perceived as too expensive to research. Obvious recruitment solutions involve invoking the saying where you go I will go, in order to nd the participants, which means searching in the right places for the people you need. This may require The incentive must be appropriate here and now bias, and prefer their engagement, any chance of participation is lost, so rapport is critical and establishing trust is essential. This requires igniting an enthusiasm in your potential respondent and having robust privacy assurances in place. Having identied one eligible original saying and add your people Snowball sampling from a base maximise access. respondent allows researchers to time for the recruitment to take place, social groupings and take niche communities takes time. By their very nature, hidden populations can be hard to nd. Such studies either require some previous knowledge of the target sample to identify initial respondents or sheer hard thinking on the part of the accessing vulnerable, socially stigmatised, or other groups. It is easy to trivialise this method research and brings with it selection interest of the respondent without will be my people. because building pathways into informal recruiters serves as an aid to must also be tailored to pique the rather than later. The subject matter asylum services, and community Of course, you must allow enough However, working with respondents as and argue that a refer a friend respondent, we can build upon our groups in person and online to are isolated, with a poor social network. reward for participating sooner engaging voluntary services, including clubs, food banks, churches, if the respondents you are looking for access seemingly impenetrable advantage of identied respondents to provide an expanding set of potential contacts. The premise is that a bond exists between the original recruit and others within the same population, allowing referrals to be made. Of course, there are limits, especially approach only applies to qualitative bias that means extrapolation is not possible. But this respondent-driven sampling can be carefully tracked by limiting referrals from one base respondent. Each referee is treated as a new base respondent (again, limiting the number of referrals each time) and you can turn your snowballing efforts into multiple snowballs, thereby increasing condence levels through weighting. Such a bottom-up approach to eldwork and recruitment is a far more efcient way to uncover hidden populations (as opposed to top down, and hoping they appear in your large samples) and by mathematically limiting and, subsequently, tracking referrals, it is possible to build robustness into the nal data. Tara Lyons is managing director at Indieeld 26 Impact ISSUE 44 2023_pp20-27_Report.indd 26 07/12/2023 14:52