Weighing incentives in subject recruitment
How high should payments go?
For researchers and IRBs there is an ethical paradox in behavioral studies involving populations that are hard to engage.
On one hand, these populations likely need interventions and programs tested in like individuals as much or more than the general population. On the other hand, they might have more obstacles to study enrollment, so recruiting participants might require incentives that raise red flags for IRBs.
Researchers who attempted to walk this line in one study involving low income, urban parents of pre-schoolers found that their recruitment incentives may have been too cautious, says Deborah A. Gross, DNSc, RN, FAAN, professor, Leonard and Helen Stulman Endowed Chair in Mental Health and Psychiatric Nursing at Johns Hopkins School of Nursing in Baltimore, MD. Gross received grant funding for the study by the NIH/National Institute for Nursing Research when she was on the faculty at Rush University College of Nursing in Chicago.
"In anticipation of problems around coercion, we made our incentives low," Gross says. "But now that we've collected data, I think we made it too low."
Finding the right balance is difficult.
"The IRB approved our incentive because we made it low enough to avoid undue influence, but I suspect it was so low it didn't work," she adds. "So how high is high enough, but not too high?"
Down to cases
The result is essentially a case study of how researchers and IRB members attempted to find the right balance between adequate incentives for recruitment and retention and appropriate participation fees. For example, if fees are too high they may lure participants into a study they might otherwise find counter to their family's best interest.
Study's purpose: Investigators wanted to study the success of an intervention program aimed at improving parenting among low-income parents of children between the ages of two and five years of age.
They targeted populations in the urban settings of Chicago, IL, focusing predominantly on minority parents whose incomes were low enough to meet eligibility requirements for subsidized child care services.
The target population included single parents and people who worked 30 hours or more at very low-wage jobs.
"This population is hard to engage because these are parents who have a lot on their plates," Gross says.
The goal was to teach parents the skills they would need to prevent later behavioral and social problems among their children.
Recruitment and retention methods: Researchers decided to recruit parents who attended day care centers that served low-income families.
The families were asked to participate in exchange for these incentives:
- Thirty dollars for each of four assessments, including assessments at baseline, post-intervention, six month follow-up, and one year follow-up;
- Free copies of four 15-minute videotaped free-play sessions with the parent and child;
- Free dinners at each two-hour intervention sessions;
- Free child care during intervention sessions;
- Discounts on child care center co-payments of 20% with a $5 minimum during the 12 weeks in which participants attended the intervention sessions; this incentive was added on for a separate study when the first study's incentives did not achieve desired enrollment;
- The intervention sessions were held at the child care center where participants' children already attended, and they were scheduled to start right at the time participant parents normally picked up their children, from 5:30 to 7:30 p.m. or from 6-8 p.m. weekdays.
Results of recruitment strategy: "After all the incentives we offered, we still found that relatively few parents enrolled in the study," Gross says.
When the child care center discounts were added to the incentive package, study enrollment improved by 15%, but this additional incentive did not improve attendance rates, she adds.
These kinds of results are unfortunate from a statistical standpoint and can result in unclear answers to the study questions.
The study might have recruited subjects from other venues, but investigators had determined that a childcare agency that they already used was the best suited for a variety of reasons.
"One, the mission of early childcare centers is to promote the health and well-being of children and their families, and I saw the parenting groups as contributing to this existing mission," Gross says.
"Second, we thought it would be convenient because their children already were there, and they had to pick up their children anyway," she adds. "So why not give them a night off of cooking dinner."
This reason had a lot of appeal on the face of it, she says.
"But what we have come to realize is that parents' work schedules vary, and for a number of reasons, parents don't come to these evening sessions," Gross says.
These reasons include the following:
- They can't leave their work early enough to attend the parenting group sessions.
- By the time the parenting sessions end, it's dark out and some parents are reluctant to take home public transportation after dark.
- Parents might have school-age children at home, and while they could bring them along for the free child care, they didn't have time to pick them up after work before heading to the child care center.
"We'll continue to look for the perfect venue, if there is such a thing," Gross says. "We'll have to offer different pathways."
These could include offering the intervention on the weekend at a different setting, since child care centers often are not licensed for use on the weekend.
IRB and researcher discussion of recruitment incentives: "The IRB has been fine with the research incentives," Gross says.
"We rationalized the $30 payments for completing the assessments as based on an hourly wage of $15 per hour for two hours," she explains.
"Where we have always struggled is with the notion that when you give an incentive for a discount or cash incentive, how much is enough to motivate behavior change without being coercive?" she adds.
This is an especially problematic concept when subjects are from low-income families.
"I am sure if we had offered parents $100 for every session they attended, we'd get a much better attendance," Gross says. "But then you have to ask yourself what these people are not doing in order to attend our sessions."
For example, one parent who repeatedly signed up for the study, but never attended a single group session was asked by one of the study investigators why she never attended. The woman responded that she wanted to become a better parent to her three-year-old, but she also had a 15-year-old at home. And if she wasn't home when her teenager came home from school then she was worried he would be recruited into gangs, Gross explains.
"Every day, parents are reprioritizing the demands on them, so you don't want to offer an incentive that would have them prioritize their demands in a way that's not healthy for their family or for them," she says.
"You can't just give them whatever the market would bear because you might encourage them to make unwise decisions," Gross says.
Another example would be if a parent left his or her job early to come to the group. But then this could jeopardize the parent's employment status.
"That's the quandary low-income parents face," she says.
"I think IRBs are in a tough spot when deciding these issues," Gross says. "They're at arms' length from the research, and they're trying to make wise decisions."
But there needs to be more research on what is the best price for incentives and the balance between an incentive that is high enough to achieve the necessary enrollment and low enough to prevent undue inducement, she explains.
"I don't think anybody has that answer," Gross says. "I would want IRBs to invest in studies that try to answer that question."