First, to minimize attrition and control for the effects of increased attention, participants randomized to the FME group did receive a minimal intervention.
Data were collected on design, intervention characteristics, target group, recruitment methods, delivery mode, number of sessions, attrition rates, control group, outcome measures and effect sizes (post-test and at follow up of at least 3 months).
Additionally, to reduce the risk of attrition, the control group will receive monthly health education sessions unrelated to qigong, commencing at the point at which the intervention group starts the weekly group follow-up.
Attrition of controls was due to refusal (28.2%) and to nonresponse (5.1%).
According to Ball (2003), performativity is "a culture and mode of regulation that employs judgments, comparisons and displays as means of incentive, control, attrition and change".
Two studies report a RA smaller than the lower limit of the 95% CI, equivalent to a higher than expected attrition in the control group (figure 2).
Relatively few of the many available Web-based interventions have been carefully evaluated in well-controlled clinical trials (Kiluk et al. 2011), and the conclusions that can be drawn from many studies are constrained by high levels of dropout, high attrition, and weak control conditions (e.g., waitlists).
As was the case for treatments, we also investigate the presence of potential attrition bias for controls by regressing of the key outcomes of interest, measured at the baseline, on an attrition dummy.
Efforts will likely require meta-analyses of existing and future telomere length GWAS to increase power to detect common variants of small effects while stratifying by age groups defined by attrition rate and controlling for environmental factors.
