: 285 Clinical trial of incontinence garments: recognition of the possible influence of the Hawthorne effect

The results of clinical trials must be interpreted with care, recognizing that they may be affected by factors other than the items being tested. Different garments were routinely supplied from two distribution centres in Edinburgh, Urocare to the majority of patients in North Lothian and Hygi to those in South Lothian. One hundred patients were recruited and a crossover comparative trial carried out. The response in the two areas was different. Whereas patients in South Lothian found no significant difference between the two garments, those in North Lothian rated the Hygi garment better in terms of comfort (p=0.01), leakage (p<0.001), odour (p=0.01) and avoidance of skin problems (p=0.01). It is suggested that the difference in response may be explained by the Hawthorne effect and this should be taken into account when planning future equipment trials