But Stephen Gorard, professor of education at Durham University, who has previously led research into the similar Philosophy 4 Children project, said the loss of the data from seven schools in the treatment group, which amounts to more than 21 per cent data in the trial missing, means «there is huge potential for bias in this trial.» (schoolsweek.co.uk)
Although we know that there is great potential for bias when we compute value - added scores for teachers working in different schools, we do not yet know the extent to which this potential is actually realized. (carnegieknowledgenetwork.org)
They looked at 25 studies that compared brushing alone or brushing + flossing and found that there was very little evidence for flossing with a large potential for bias. (wellnessmama.com)