While it's not worth it for me to pay $30 for the full paper of the main trial ('IDEA') cited, from the abstract I wonder about the conclusions drawn. * What i

While it's not worth it for me to pay $30 for the full paper of the main trial ('IDEA') cited, from the abstract I wonder about the conclusions drawn. * What if the specific content of the full bundle of interventions – including a certain kind counseling & low-calorie diet – actually serves to make the tracker seem relatively less-important? (It might be the case that someone given just a tracker would focus on it, while those with the other interventions – all participants – would be more likely to view it as superfluous.) * What if those losing less weight are nonetheless more satisfied with their progress, perhaps because they've gained in other ways? (What if they've lost less weight because they've gained muscle weight? There's no hint whether this was measured.) * It's not clear how the "…those who employed the technology were no more physically active than those who didn’t… {t]hey also weren’t more fit" conclusion was drawn. Self reports? (How do you know someone's true activity without a dedicated tracker?) * What specific tracker & software was used? Results could be very sensitive to UX issues – something minimal & academic might be hard-to-use and easy-to-ignore compared to (say) popular commercial smartphone apps. They only mention a 'website', not an 'app', in their abstract. (I would not often visit a website to check my activity or check my diet, but I view my wrist-worn Fitbit device, and its app interface, a dozen or more times a day.) I suspect that to get a clearer reading of what just-a-tracker might do, I'd prefer a minimal focused study, along the lines of: * every participant is asked their weight-loss goal, then sent a questionnaire once each week to self-report progress * some participants are also given a commercial tracker, and their weekly questionnaire also asks if they're using it * at the end, total progress is evaluated (and automated activity-tracker usage stats collected) That could disentangle the other-interventions and maybe-not-state-of-the-art academic interface from the results.