Assuming that trackers have this habit-building effect: While we then would expect the effect to have have been larger if they'd handed out the trackers at the

Assuming that trackers have this habit-building effect: While we then would expect the effect to have have been larger if they'd handed out the trackers at the beginning of the study, some participants should have benefited from this effect even mid-study. One hypothesis here is that the trackers provided a frame of reference that anchored participants to some goal like 10'000 steps daily while the participants who had less direct feedback were free to expand their goals as their fitness improved. Some things seem much more arduous to me when I track progress while doing them.