 Bates notes that the correlation in the theories of Risley and Grierson is not surprising because Grierson was 

Another event that occurred in 1901 and which related to Risley was the official approval of an India-wide ethnographic survey, intended to be conducted over a period of eight years and using in part the anthropometrical methodology established for Risley's survey of Bengal.Superintendents were appointed to each Province and Presidency and grants of £5000 per annum were given for the eight-year period.Bates considers that the results of this effort, which included works by Edgar Thurston and Robert Vane Russell, were rarely "quite so thorough, even by Risley's standards."