Three pilot studies looked at women who had not attended for cervical screening following a computer-generated invitation to a health authority clinic. From these a typology of reasons for non-attendance for computer-managed screening has been developed, specifying inaccessibility, ineligibility, unsuitability, failure of communications, misclassification and refusal because of practical problems, inappropriate beliefs or attitudinal barriers. Underlying the typology are issues connected with the inaccuracy of the database, service organization and provision, and the characteristics of the women themselves.