These surveys have been carried out in Africa, Asia, Latin America, and elsewhere roughly every five years since 1984 and 1995 respectively. The first to ask about FGM was the 1989–1990 DHS in northern Sudan. The first publication to estimate FGM prevalence based on DHS data (in seven countries) was written by Dara Carr of Macro International in 1997. Type of FGM
Questions the women are asked during the surveys include: "Was the genital area just nicked/cut without removing any flesh? Was any flesh (or something) removed from the genital area? Was your genital area sewn?" Most women report "cut, some flesh removed" (Types I and II).Type I is the most common form in Egypt, and in the southern parts of Nigeria. Type III (infibulation) is concentrated in northeastern Africa, particularly Djibouti, Eritrea, Somalia, and Sudan. In surveys in 2002–2006, 30 percent of cut girls in Djibouti, 38 percent in Eritrea, and 63 percent in Somalia had experienced Type III. There is also a high prevalence of infibulation among girls in Niger and Senegal, and in 2013 it was estimated that in Nigeria three percent of the 0–14 age group had been infibulated. The type of procedure is often linked to ethnicity. In Eritrea, for example, a survey in 2002 found that all Hedareb girls had been infibulated, compared with two percent of the Tigrinya, most of whom fell into the "cut, no flesh removed" category.
In Sudan in 2006, a significant percentage of infibulated women and girls reported a less severe type. Types
Standard questionnaires from United Nations bodies ask women whether they or their daughters have undergone the following: (1) cut, no flesh removed (symbolic nicking); (2) cut, some flesh removed; (3) sewn closed; or (4) type not determined/unsure/doesnt know. The most common procedures fall within the "cut, some flesh removed" category and involve complete or partial removal of the clitoral glans. The World Health Organization (a UN agency) created a more detailed typology in 1997: Types I–II vary in how much tissue is removed; Type III is equivalent to the UNICEF category "sewn closed"; and Type IV describes miscellaneous procedures, including symbolic nicking. Type I
Type I is "partial or total removal of the clitoral glans (the external and visible part of the clitoris, which is a sensitive part of the female genitals), and/or the prepuce/clitoral hood (the fold of skin surrounding the clitoral glans)". Type Ia involves removal of the clitoral hood only. This is rarely performed alone. The more common procedure is Type Ib (clitoridectomy), the complete or partial removal of the clitoral glans (the visible tip of the clitoris) and clitoral hood. The circumciser pulls the clitoral glans with her thumb and index finger and cuts it off. Type II
Type II (excision) is the complete or partial removal of the inner labia, with or without removal of the clitoral glans and outer labia.