On two separate study days, corresponding to different phases of their menstrual cycle, stimuli were presented while exposed to male axillary pheromones and under a control condition (no pheromone). Thirty-two female undergraduates, half of whom were contraceptive pill users, rated male vignette characters and photographs of male faces on aspects of attractiveness. The present study investigated the effects of exposure to male axillary secretions on female ratings of the sexual attractiveness of male stimuli. The aim of this article is to provide guidance on the use and interpretation of Bland Altman analysis in method comparison studies.Previous research has revealed that natural and synthetic pheromones can enhance ratings of opposite sex attractiveness. Acceptable limits must be defined a priori, based on clinical necessity, biological considerations or other goals.
The B&A plot method only defines the intervals of agreements, it does not say whether those limits are acceptable or not. Data can be analyzed both as unit differences plot and as percentage differences plot.
The B&A plot analysis is a simple way to evaluate a bias between the mean differences, and to estimate an agreement interval, within which 95% of the differences of the second method, compared to the first one, fall. In 1983 Altman and Bland (B&A) proposed an alternative analysis, based on the quantification of the agreement between two quantitative measurements by studying the mean difference and constructing limits of agreement. However, correlation studies the relationship between one variable and another, not the differences, and it is not recommended as a method for assessing the comparability between methods. Correlation and regression studies are frequently proposed. The correct statistical approach to assess this degree of agreement is not obvious. In a contemporary clinical laboratory it is very common to have to assess the agreement between two quantitative methods of measurement.
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