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A major problem that has dogged research into body image disturbance in anorexia nervosa concerns the diversity of measurement procedures employed in studies of body size estimation. Many researchers believe that results obtained with different procedures cannot meaningfully be compared with each other, because the methods used measure different aspects of the body image. A meta-analysis of 33 body size estimation studies was conducted to investigate whether methodological differences do indeed influence outcome. This analysis revealed a general overestimation of body size among anorexia patients. Although a difference in mean effect size was found between studies using Body Part and Whole Body methods, this difference was absent when only the most commonly used Body Part method, the visual size estimation procedure, was considered. Among Whole Body methods, silhouette methods could not be distinguished from the rest in terms of effect size. It was concluded that Whole Body methods and the visual size estimation procedure assess correlated aspects of the body image.

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With the growing realisation by psychologists of the need to take account of response biases in perception and memory, the lack of a simple and realistic model to enable ‘sensitivity’ and ‘bias’ to be measured separately in complex tasks is becoming acute. Though signal-detection theory (TSD) has proved very useful in two-alternative tasks, it is virtually intractable in multiple-choice tasks; for this reason experimenters have tended to resort to Luce's Choice Model (LCM) as an approximation to it. The relationship between TSD and LCM, however, though close in the two-alternative case, becomes increasingly tenuous as the number of alternatives is increased. Nevertheless the substitution may still be made, provided certain cautions are observed: computer simulations have been used here to study both forced- and unforced-choice tasks, and establish guidelines for experimenters who wish to apply a two-factor analysis to data from complex tasks.