This original study - based on a specially designed survey of 1,621 households in Uttar Pradesh State, northern India - is concerned with ways of improving the measurement of women's participation in the labour force. What types of questionnaire provide the most accurate data? Does the sex of the interviewer or the respondent influence the outcome? Do proxy-respondents (people answering for the women) provide different replies from the women themselves? The authors address these issues and show that appropriate survey techniques and questionnaire design can lead to a more accurate and complete.