In 1930 Hogben moved to the London School of Economics, in a chair for social biology. There he continued to develop the Hogben Pregnancy Test. Previous pregnancy tests required several days to carry out and resulted in the deaths of mice or rabbits. Hogben's pregnancy test took hours and could be carried out without harm to the frogs, which could be reused for future tests. It became the major, international pregnancy test for about fifteen years, from the mid-1930s through the 1940s.