[4][5][6] Walker's system includes images of each hair type to aid classification.
[12][13][14] The system has added new subtypes since its original version to Type 1.
[15][2][16][17] There has been a lot of debate in the black/curly hair community over the validity of the classification.
[18] The Walker system has been judged an improvement on some earlier systems that ranked black hair as less desirable, but is criticized for not taking into account the full variation in density and scalp types or that people's hair can vary on different parts of their heads.
[19] Research in the International Journal of Women's Dermatology has suggested Walker's curl-classification system may be useful in conversations about alopecia and other health conditions.