ABSTRACT
In allied health and educational fields, where resources are limited and the same person may be conducting the study and administering the intervention, particular care needs to be given to masking. Nevertheless, there is evidence that, even with relatively objective tasks, researcher bias can creep in. In medical trials, the large amount of evidence for researcher bias on measures has led to a general consensus that outcome assessments should be done by someone who is unaware of who was in the intervention or control group. Lo & Field define conflict of interest (COI) as: 'a set of circumstances that creates a risk that professional judgement or actions regarding a primary interest will be unduly influenced by a secondary interest'. Typically, people think of COI as involving money. Unfortunately, there is evidence that conflict of interest leads to bias, with more positive results being reported when it is present.
