Fig. 6. An infographic depicting the change in percentages of total papers sampled reporting studies in 2009 and 2019 that used both sexes, a single sex, omitted sex, papers reporting studies that used an optimal design or analyses for the discovery of possible sex differences irrespective of discipline.

Optimal design refers to relatively based sample size and use of males and females consistently across the experiments whereas optimal analyses refers to the use of sex as a discovery variable. Although the percentage of studies in the sample of neuroscience and psychiatry papers analysed has increased the use of optimal design and analyses has not changed as much and remain at low levels. There are nine times the percentage of male-only compared to female-only studies.