Table 3 Summary of recruitment challenges we encountered and suggested solutions

Recruiting insufficient numbers in locality of research institutions and therefore needing to recruit nationwide

Ensure considerations and resources for travel or alternatively online data collection are built into grants applications, research protocols and timelines [17]

Consider inclusion of a Public and Patient Involvement (PPI) panel to advise all aspects of the study, including recruitment [18]

Difficulty adhering to research timelines due to unsuccessful early recruitment efforts

Ensuring flexibility in terms of time and contingency plans, and

Allowing for transcription and data analysis to run concurrently with further recruitment and data collection [19]

Challenges with capturing the attention and interest of gatekeepers during initial contact and building rapport

Contact by phone and not email

Utilising existing connections where possible

Providing study information as succinctly as possible

Consider offering resources, data collection relevant to the goals of the organisation, or expertise [20] (in our case infant feeding workshops/information) to allow a sense of reciprocal input

Maintaining buy-in from gatekeepers due to the complicated logistics of carrying out screening questionnaires prior to inviting eligible participants to a focus group, and the possibility of excluding people

Avoiding too many steps in the process and pre-empting logistical barriers [20]: consider providing the inclusion criteria with details of pre-arranged focus groups, allowing participants to self-screen. Demographic questionnaires during data collection can be used to measure eligibility

Difficulty recruiting via social media compared with other routes: difficult to find appropriate groups/pages to target, with correct demographic and sufficient reach

Consider whether sponsored advertisements on social media may be helpful, and build this into research budget

Approaching group/page administrators to post material the group to engender sense of legitimacy and relevance [21]

Identifying social media ‘champions’ who could assist in online dissemination [22]

In areas with limited organisations to contact for recruitment (such as NI), there was a risk of research fatigue among those who are regularly approached for research

Consider whether collaboration with another research study to combine data collection for answering multiple research questions is feasible, while carefully assessing burden on the participant

Seasonality of services and participant availability e.g. parent group closing for the summer

Make a list of organisations and their schedules early on so approaching those who are seasonal can be prioritised [23]

Approaches used successfully recruited female parents/carers but did not result in recruitment of fathers/male carers

Additional and specific recruitment efforts for recruiting male parents should be researched and planned in advance, where fathers/male carers are explicitly invited [24]