Graduate school that does not require a statement of purpose
Two groups of departments often do not request SoP:


The departments, within which the diversity of the research among the corresponding faculty members are such noticeable that the applicants would be admitted to the program based on the merit, firstly. Then, they would have sufficient time to communicate with the faculty members and choose their desired research track.
The departments, within which the interview with applicants is routine before any offer of admission. So, one might conclude that the coherency in view of the research interests with the faculty members will be investigated within the interview.