Summary•The purpose of this paper is to contribute to the debate on issues related to the reliability and validity of measurement of challenging behaviour (behavioural difficulties) in learning disability. A number of practical, theoretical and methodological issues are discussed that have significance for the nurse both as practitioner and/or researcher in learning disability. These issues are equally important to both provider and purchaser of health care in order that resources can be most effectively targeted.•The term ‘challenging behaviour’ would appear to be used both in literature and research synonymously with behavioural difficulties, this has implications for nurses in both their clinical practice and/or research. The author concludes by identifying a need to replace the term challenging behaviour, with ‘behavioural difficulties’. It is argued that such a term is much more explicit in meaning and amenable to operational definition, thus enabling empirical study. Such a proposal will not be accepted by all as justifiable; this is because some might argue that adopting the term behavioural difficulties may be a retrograde step that perpetuates negative imagery and inappropriate labelling of people with a learning