According to the Times of India, a study examined students' performance and attitudes in mathematics and science; verbal skills; and attitudes towards school, gender stereotypes, aggression, victimization and body image. The total sample included 1,663,662 participants in 21 different countries. They found insufficient evidence to demonstrate any difference in these attitudes between boys and girls in single-sex classrooms. The research, which analyzed 55 years of data, refutes theories that girls thrive when separated from boys and that boys perform better when they have a curriculum specifically tailored to them. Although single-sex schools achieve outstanding exam results, there is no concrete evidence that this is the result of separation of boys and girls. Since many single-sex schools are selective, their excellent exam results may be due to pupils having an advanced academic level and more challenging teaching programmes. Single sex classes are facing failure due to lack of adequate training and infrastructure. Global research conducted by the University of Nebraska showed that 71% of teachers believe they are not adequately trained to transition to single-gender classrooms. According to a report published in the journal Science, researchers wrote: “Education based on sex segregation is deeply misleading and often justified by weak, cherry-picked or misunderstood ideas.