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Table 1 Barriers anticipated or encountered, strategies implemented, and implications of these strategies

From: Processes for engaging and retaining women who are experiencing adversity in longitudinal health services research

Sampling frame
Anticipated difficulty accessing the population of interest [1] (pregnant women experiencing adversity)Venue-based sampling [10]We identified a health service (antenatal clinics at public hospitals) that a large proportion of the population would visit, and that researchers could recruit at. We worked with state government partners to identify eligible hospitals serving women where both the postcode-level disadvantage, [9] and children’s developmental vulnerability according to census-level data, [11] were high. We met with antenatal clinic managers to understand client demographics (i.e. level of adversity, birth rates, how close patients live to hospital), and how clinics were run (i.e. triage, wait times, new/high risk/review appointments), to decide which clinics to recruit from.We successfully recruited a large cohort of women experiencing adversity. Of the 5586 women who completed the BRF survey (see Figure), the average SEIFA was 972.6 (Australian average is 1000; lower scores reflect greater adversity). Of these, 78.3% lived in postcodes from SEIFA quintiles 1–3 (experiencing greatest adversity), compared with 60% nationally [12]. SEIFA was 953.6 for 1427 women who were eligible for the RCT, compared with 979.1 for 4159 ineligible women.aIdentifying trial sites that provided care for a high prevalence of women experiencing socioeconomic adversity was a key factor in recruiting the large cohort. Initiating relationships with the antenatal clinic managers was aided by the state government partners. The scoping work to identify suitable clinics, build relationships and establish processes with clinic staff took approximately 6 months from first contact to commencing recruitment, which included obtaining HREC approval. Face-to-face meetings with clinic management were crucial for developing a partnership and processes for data collection.
Anticipated selection bias if recruitment conducted by clinic staff [6]Researcher-led recruitmentWe used researcher- rather than clinician-led recruitment to minimize burden on the already-busy antenatal clinic staff and avoid the possibility of gatekeeping or cherry-picking by clinician-recruiters.Recruitment by researchers in antenatal clinic waiting rooms was acceptable to women and feasible: of 6977 eligible women surveyed, 5586 (80.1%) completed the survey; 468 (6.7%) started but left the waiting room before finishing (e.g. for an appointment); and 923 (13.2%) declined. These numbers are consistent with the findings of the recruitment pilot study (described below) [8].There were no data available for the 20% of non-responding women to compare their demographics and levels of adversity with participating women, so this may have implications for the generalizability of the RCT findings.
Recruitment and obtaining consent
Potential for infeasible or unacceptable recruitment processes [1]Pilot recruitment processesRecruitment processes were piloted with all women (N = 189) attending antenatal clinics at 2 participating hospitals on 3 consecutive days.166/186 (89%) of eligible women completed the survey. The high response and zero missing data demonstrated feasibility and acceptability of the recruitment process [8].The pilot was invaluable for planning recruitment for the RCT. Strong research-clinic relationships were forged using this initial collaborative process, and the pilot clinics acted as champion sites for the larger RCT.
Recruitment started slower than necessary to achieve sample sizeExpand catchment areasWe worked with clinic managers to identify additional clinics that researchers could recruit from.61/722 (8.4%) additional participants were recruited from 3 additional clinics, which contributed to recruiting the required sample size [4].HREC approval was required for protocol modification. Additional meetings and training between research team and clinic staff were necessary.
Extend recruitment phaseThe number of eligible women attending clinics was lower than anticipated based on previous annual birth rates. The recruitment phase was extended by 6 months (coordinated by trial directors, the Australian Research Alliance for Children and Youth – see Acknowledgements)198/722 (27.4%) additional participants were recruited, which contributed to recruiting the required sample size [4].Substantial additional funding was required to extend the research and intervention salaries; changes to contracts with staff and local governance organizations; changes to contracts with funding and government partners. The slower than anticipated recruitment rate had the greatest potential for negatively impacting the RCT’s statistical power and generalizability. Extending the trial dates and funding therefore made the greatest impact on the trial’s eventual validity.
Recruitment flyer available at clinicsFlyers were left in participating hospital clinics, and some additional clinics of General Practitioners (primary care doctors providing shared antenatal care) for the duration of recruitment period. Interested women could contact the project coordinator and complete the BRF survey by phone.19 women contacted the research team after seeing a flyer and completed the BRF survey by phone. 5/19 (26%) enrolled in the RCT (1 declined, 13 were ineligible), contributing 0.7% of the final enrolled cohort of N = 722.Time was required to design flyer, obtain HREC approval for protocol modifications, and conduct informed consent and complete the BRF survey over the phone with women, plus printing costs.
Anticipated low literacy [7]Face-to-face recruitmentResearchers offered to go through the recruitment materials (information statement and consent, and survey) verbally with each woman.Women requested a verbal explanation infrequently at recruitment (no data collected/available to describe numbers). Note: women with insufficient English to participate in face-to-face interviews were excluded from the trial (667/9511 (7%) when first approached in clinic waiting rooms) [12].The research findings may not generalize to women with insufficient English to participate. In addition, women with low literacy may be overrepresented in the 923/6977 (13%) women who declined to complete the recruitment survey [12].
ReadabilityAll printed materials were written at a Grade 6 level or less (primary/elementary school).
Recontacting eligible women for formal enrolmentOn-the-spot bookingsRecruitment began with a staggered approach across the participating sites. For the first 2 months, when recruitment was taking place at 4 Victorian sites, researchers invited women to complete the BRF, recorded the details of eligible and interested women, and attempted to recontact them in the following days to book the enrolment home visit. However, recontacting women proved difficult. The scheduling process was changed to book the enrolment visit with women on-the-spot, once the BRF survey was complete.For the first 2 months, across the 4 initial Victorian sites, 61/172 (35%) eligible women enrolled, and the average time between completing the BRF survey and the enrolment home visit was 22 days (range 2–112). For an equivalent 2-month period once on-the-spot bookings were introduced at the same 4 sites, 48/102 (47%) eligible women enrolled with an average time of 18 days (range 0–91) between BRF survey completion and the scheduled enrolment visit.On-the-spot bookings required an online, confidential, real-time calendar that was accessible to all researchers via internet-connected tablets (which was the primary method for data collection for right@home). For this study, the calendar was custom-designed by the research institute’s IT department. Funding was necessary for the IT contract, tablets and plans.
Inaccessible or intimidating study informationAppealing, promotional study materials [5]Designing study materials to be appealing and promotional. These included:
• Giving women an enrolment pack that included a magnetized card with the study details, contact information and enrolment appointment details;
• Adding a simple, 1-page colorful flyer to the enrolment pack to precede the lengthy information statement and consent form;
• Increasing the font and spacing on the detailed information statement and consent form;
• Hanging simple posters and leaving flyers in the waiting rooms that described recruitment;
• Placing a placard with the researcher’s name “[Name] is recruiting today” at reception desks, and asking reception staff to tell women about recruitment and encourage interested women to speak to the researcher.
There were no data to describe the usefulness or otherwise of these strategies; however, anecdotally, participants told the researchers that they used and referred to the magnetized cards frequently and, when approached by the researchers in clinic, women often said they had seen the placard and/or posters. There was no specific feedback on the flyers, or font and layout of the information statement; however, as they did not appear to hinder the research processes, they were retained for the duration of recruitment.Time required for research team to design materials and obtain HREC approval, plus cost for printing materials. Using posters, flyers and placards relied on frequent conversations with clinic staff, which was good for relationship building and required researchers to be sensitive and flexible regarding the needs and pressures of busy clinics.
Data collection and measurement
Anticipated low literacy [1, 7]Direct data collectionAll data were designed for direct collection via face-to-face visits or phone interviews, unless visits/phone calls were not possible (see point below).There were minimal missing data over time, e.g. proportions of missing data for the sensitive risk factors asked at enrolment (e.g. drug use, domestic violence) ranged from 0 to 5% per item, suggesting that items were acceptable and understandable. Further, we retained high proportions of the originally-enrolled sample to 2 years (82.5%), suggesting that the data collection strategy supported retention. Note: women with insufficient English to participate in face-to-face interviews were excluded from the trial (667/9511 (7%) screened in clinic waiting rooms) [12]Research findings may not generalize to women with insufficient English to participate. In addition, women with low literacy may be overrepresented in the 923/6977 (13%) women who declined to complete the recruitment survey [12].
Blocked phone numbers would not have identified the callerPhoning and texting from unblocked, active mobile/cell numbersThe clinic staff and intervention workforce advised the field researchers to use unblocked phone numbers to contact participants instead of the standard, institute-based blocked numbers. This allowed participants to identify the caller in advance. The mobile/cell phones also allowed for conversations with participants via text message, which the research team relied on heavily for booking assessments. Similarly, researchers used text messages to follow-up unanswered calls (see below) instead of leaving voicemails, because the cost of accessing voicemails may have deterred some participants from listening to them.There are no data to describe whether these strategies supported retention; however, our researchers relied entirely on mobile/cell phone and text message contact.Costs for purchasing mobile phones and plans, which were more expensive than using the institute-based landline phones.
Challenges in contacting participants via phone call
Challenges in contacting participantsEnough contact attempts to give participants opportunity to provide data without causing botherFor each assessment, we implemented a 4–5 month window for data collection before a participant was ‘lost to follow-up’ for that time point. A protocol specifying a maximum number of contact attempts was trialed, ranging from as few as 8 contact attempts per assessment to more than 30. For this RCT, a contact attempt referred to a researcher’s attempt to contact a participant including interaction between the researcher and participant that followed the attempt directly, e.g. texts or phone calls back and forth between the researcher and participant in 1 day, or a text sent by a researcher on 1 day which the participant replied to the next day. Contact attempts included emails but excluded the standard reminder phone calls/texts, postal surveys, and Facebook messages that are described below.During data collection, the field researchers found that 8 contact attempts were too few to maximize data collection with the hardest-to-reach participants, but were concerned that 20–30 attempts bothered participants. By the end of the 2 year follow-up, the team had established a contact process that allowed for approximately 16 contact attempts per assessment period. This revised protocol was supported by the contact notes; these were retrospectively analyzed for a random selection of 100 participants approached for the 2 year follow-up. For this random sample, an average of 3 contact attempts was needed to complete the assessment (range 1–20). 68 were completed in 1–3 attempts; 16 in 4–6 attempts; 4 in 7–10 attempts; and 4 in 11–20 attempts. 8/100 were not contactable. There was no evidence of differences between trial arms in the number of contact attempts made.HREC approval was required for protocol modifications. Employing a specific number of contacts (e.g. 16) meant researchers needed to target their efforts to optimize each attempt, e.g. calling at different days, different times, after hours, weekends etc., and this approach was designed by the research coordinator and then monitored collectively by the field researchers. Providing after hours/weekend options to participants also requires employing a research workforce who can work flexibly.
Minimizing burden of data collection, and anticipated loss-to-follow-up and withdrawals over timeData linkageParticipants were invited to consent for linkage to additional data sources due for future collection, to minimize the burden of future data collection, and maximize the longitudinal data available where participants are lost to follow-up. This included visits to the usual child and family health service (CFH, consent collected at baseline) and the Tasmanian Kindergarten Development Check (TKDC), the Victorian School Entrant Health Questionnaire (SEHQ) and the National Assessment Program – Literacy and Numeracy (NAPLAN) (consent collected at 1 year).711/722 (98.5%) of enrolled participants consented to CFH service data linkage. 420/485 (86.6%) of enrolled Victorian participants consented to linkage with the SEHQ, and 197/237 (83.1%) of enrolled Tasmanian participants consented to linkage with the TKDC. 616/722 (85.3%) of all enrolled women consented to NAPLAN data linkage. These proportions are all higher than the proportion of participants providing data at 2 years (82.5%) and higher than the cohort who would be expected to complete assessments to school entry.HREC approval was required for protocol modifications. There will be future staffing costs necessary to conduct the data linkage and analysis. There is a risk that the future managers of the state and national datasets will decline linkage requests; however, authors have already accessed linkage for SDQ and NAPLAN for other projects [13]. Furthermore, linkage is a fantastic opportunity for obtaining long-term, representative data on a diminishing cohort.
Retention and attrition
Minimizing instances that participants fail to attend direct assessmentsReminders for direct assessments (data collection)Participants’ plans changed day-to-day, so the research team employed several reminder processes. Text messages were sent on Mondays to all participants with a direct assessment scheduled in the week. A phone call was made the day before the visit to confirm and reschedule if necessary. Text messages were also sent the morning of assessments to confirm and reschedule if necessary.There were no data to describe whether these strategies supported retention; however, anecdotally, they made it easier to book and rebook assessments as participants responded and initiated contact with researchers. For example, for the 596 women who provided data at 2 years, 119 (20%) rescheduled the follow-up assessment once or twice, and 13/596 (2%) rescheduled at least 3 times (78% completed the assessment without rescheduling), so field researchers needed to be flexible to families’ changing calendars and rebook assessments rapidly so as not to lose contact with the participant and momentum for the follow-up.Costs for purchasing mobile phones and plans, which were more expensive than using the institute-based landline phones. Researcher time was required to develop templates for text messages (to convey meaning in a short message and avoid sending lengthy texts), plus relevant HREC approval.
Reminders for phone assessmentsResearchers texted before calling, or texted after a missed call, instead of leaving voicemail. This creates an opportunity for participants to text back with a suitable time to talk, or arrange a follow up visit by text.
Anticipated loss-to-follow-up due to a participant’s changed contact detailsFlexible data collection methodsWhere the intended method of follow-up was not possible (e.g. face-to-face), participants were offered options including postal surveys or phone surveys to accommodate issues with their availability, new address interstate or overseas, low English proficiency, or personal preference.Of 596 women who provided data at 2 years, 5 (0.8%) completed a postal survey and 19 (3.2%) completed a phone instead of the direct assessment.Time was required to design assessment options and obtain HREC approval for protocol modifications, plus any printing and postage costs.
Recording a variety of participant contact informationThese were collected from participants and updated at every assessment where available: researchers recorded addresses, home phone numbers, mobile phone/cell numbers, secondary phone numbers (e.g. work), email addresses and best time to contact participants during the we ek or day.During the period from enrolment to the 2 year follow-up (actual or due), of the 722 enrolled participants, 31% moved once, 18% moved 2–3 times, and 2% moved at least 4 times (49% did not move). There was no evidence of differences between trial arms in number of address changes. With regards to primary mobile phone/cell number changes, for the 722 enrolled participants, 23% changed their primary mobile/cell number once, 13% changed it 2–3 times, and 2% changed it at least 4 times (63% did not change it). Note, proportions add to > 100% because of rounding.The cohort was highly mobile. These data underestimate the true frequency of changes because they only represent those made known to the research team, and the address and phone changes for the participants lost to follow-up are not represented. Similarly, we present the number of changes to the primary mobile/cell phone number because this was the main means for contact; however, there were many other contact changes for landline (home, work) and other (partner, parent) phone numbers. Given the frequency of changes, recording a range of contact information was crucial for retention.
Recording alternate contacts who will know a participant’s updated detailsTwo alternate contacts collected and updated at every assessment where available: name, relationship, address, email, home and mobile/cell numbers.Alternate contact use examined for a random selection of 100 participants approached for the 2 year follow-up (same sample as above). It was used once for 6 participants, and for all 6 (100%), the 2 year assessment was completed. All 6 of these participants were in the usual care group (none were in the intervention group). While the sample size is small, it suggests that alternate contacts were required more for the usual care group than the intervention group. This is likely because intervention families had more constant contact with the research team through the frequent, regular visits with intervention nurses, where usual care families did not.This cohort was highly mobile and, anecdotally, the participants often told researchers that they went in and out of contact with family members and partners, so it was important collect details for more than one alternate contact. The alternate contacts also relayed similar changes in their relationship with the participants to the researchers.
Permission to obtain new contact details from government social support programIntroduced at Baseline and completed at the 1 year assessment, participants were invited to provide consent for the research team to obtain their updated contact details (where they were not contactable through any other means) from a government social support program (“Centrelink”), which administers universal benefits such as the child care rebate plus means-tested benefits like pensions and prescription subsidies.Of 697 women invited to consent to this linkage, 604 (87%) agreed. By the end of the 2 year follow-up (December 2016), we had contacted the government department 5 times to request updated participant contact details. The time taken to receive the updated data from the department ranged from 8 days to 7 months. Overall (totaled across the 5 contact points with the department), we requested updated contact details for 81 participants; of these, we received new details for 51 (63%), including 35 (69%) phone numbers, 32 (63%) addresses, and 20 (39%) email addresses. Of the 51 participants, we were subsequently able to contact 23 (45%).Time was required to design the consent processes, and obtain HREC and government approvals. As this was a new type of collaboration for the government department, and the group responsible was restructured during the research, the process (to apply for and receive data) was time consuming and inefficient. However, subsequent requests for the RCT’s extended follow-up in 2017 (see Protocol) were far more efficient, with an average time of less than 2 weeks from request to receipt of updated contact data.
Using social media to identify participantsDuring the 2 year assessment and after the governing HREC had implemented guidelines around using social media, researchers started searching for participants who we had lost contact with using Facebook in May 2016. Those who were identifiable from their name, age, email address and location (and sometimes family members including children) on public pages were contacted by direct messenger using a standardized message about the research project.From May to December 2016, we searched for 107 participants on Facebook. We successfully identified 63 participants (59%) and messaged 61 (2 contacted the research team themselves). Of the 61 messaged, 35 (57%) saw the message (indicated by a Facebook function) and 11 (18%) responded by writing back. Responses included providing new contact details (46%), wanting to remain in the study (36%), or withdrawing (18%) from the study. Overall, of the 61 participants messaged, 20 (33%) were eventually contacted and 7 completed the 2 year assessment.HREC approval was required for protocol modification. Time was required to create a project page, to search for and identify participants via public details, and send messages. There are substantial implications for confidentiality if participants of a research trial interact with Facebook page, so the project’s page was designed as a portal for messaging, and it was not possible for participants to interact with (e.g. like or comment on) the page.
Acknowledging participants’ contribution to the studyAnnual newsletterEnd of year newsletter sent to all enrolled participants to thank them for their participation, and to provide an update on the research, achievements, preliminary findings, staff biographies and student projects.There were no data to describe whether newsletters supported retention; however, the research team considers it a way to thank participants and answer common participant questions. This type of feedback is also required by the governing HRECs.HREC approval was required for protocol modifications. Time was required to design and collate newsletter, there were costs for printing.
Remuneration for time needed for annual, face-to-face assessments$30 vouchers for supermarket chains (for groceries only) were given to participants to thank them for each face-to-face (i.e. annual) assessment completed.Participants in the aforementioned 2013 recruitment pilot study [8] were asked if remuneration would help them participate in the larger RCT; $20–$30 was the preferred voucher amount (preferred by 40% of participants; however, 21% of women reported that the amount did not matter. While we did not collect data on the usefulness of vouchers in this RCT, we know that participants used them because they commonly asked for them, and contacted the research team when vouchers needed activating or a researcher had run out of vouchers at a visit.Substantial research cost. Appeared to be important for participant engagement.
  1. BRF Brief risk facto survey, HREC Human Research in Ethics Committee, SEIFA Socio-Economic Indexes for Areas Index of Relative Disadvantage
  2. aSEIFA calculated based on data for 1424 women who were eligible and 4135 who were not eligible due to missing data