Study published: Opt-out as recruitment strategy in internet-administered CBT intervention


A study recently published in BMJ Open has examined the use of an opt-out recruitment strategy and reasons for non-participation among potential participants in the ENGAGE feasibility trial.

Photo of a person's hand answering a questionnaire

The ENGAGE study
An opt-out recruitment strategy was used within the ENGAGE feasibility trial, which tested the feasibility of a guided internet-administered cognitive behavioural therapy-based intervention for parents of children treated for cancer. Study invitations were sent to parents of children who had ended their treatment for cancer between 3 months and 5 years earlier.

First study in Sweden using an opt-out strategy
Normally, recruitments to clinical studies use an opt-in recruitment strategy, in which potential study participants can choose to participate in a study or not respond. However, the ENGAGE feasibility trial used an opt-out recruitment strategy, where study invitations were sent to potential participants throughout Sweden. These potential participants could choose between asking for more information about the study, participating in the study, or declining further contact about the study (opt-out). Those participants who did not respond within four weeks of being sent a study invitation were reminded by telephone, or were re-sent a study invitation.

Joanne Woodford is one of the researchers behind the study:

Photo of Joanne Woodford
Dr. Joanne Woodford. 

– To the best of our knowledge, this is the first time an opt-out recruitment strategy has been used in Sweden in this population. We exceeded our recruitment targets, but because of the way the study was designed, we can’t say whether this was because of the opt-out recruitment strategy.

Parents with lower levels of education opted out
Out of 509 invited parents, 164 (32.2%) opted out. There was a trend for parents with a lower level of education to opt out. The most common reasons for non-participation were: no need of psychological support, lack of time, and no interest in internet-administered self-help.

Joanne Woodford comments on the results:

– Our findings show that we need to identify better ways to widen study participation for people from more varied sociodemographic backgrounds. We also need to think ways to improve the acceptability of internet-based psychological interventions. We also need to think about parents’ lack of time as a potential barrier in the development of psychological interventions in the future.

Read the full paper ‘Opt-out rates and reasons for non-participation in a single-arm feasibility trial (ENGAGE) of a guided internet-administered CBT-based intervention for parents of children treated for cancer: a nested cross-sectional survey’. It is written by Josefin Hagström, Joanne Woodford, Agnes von Essen, Päivi Lähteenmäki, and Louise von Essen.

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Last modified: 2023-03-24