Criminology has historically been an androcentric, or male-focused and male-centered, field. Early criminologists basically ignored female crime. Those who did discuss this issue considered it to be part of females' pathology or hysterical nature, as psychologist Sigmund Freud suggested. A theory is based on some type of data, which may be collected from actual subjects (in surveys, in interviews, or by other means) or through secondary sources (e.g., analysis of court records, historical documents). Historically, criminologists studied only men or analyzed data only from men in developing their theories.