Fitting hearing aids: the effects of method of instruction. 
An experiment was conducted to examine the effect of teaching method, age and sex on older people's ability to fit their hearing aids.  Four methods of teaching were examined, three of which used visual material developed in conjunction with the Exeter College of Art.  As a result of the experiment self-instruction is the method recommended for use at Hearing Aid Centres as it reduces instructor time, leads to greater success and naturally differentiates those who are having substantial difficulty from those who manage.  It can both save technician time and reveal those on whom they need to concentrate their effort.  In this way it is evidently the most efficient.