Background There is increasing reference to complex patient needs in health care. However, little is known about how to measure patient complexity or the relationship between it and district nursing activity.

Aim To illustrate the use of group concept mapping (GCM) to conceptualise and develop items for a patient complexity assessment instrument to be used by district nurses.

Discussion The first phase of this research used GCM conceptualisation and consensus methodology to identify items for a community-based patient complexity instrument. GCM helped to provide a conceptual understanding of community-based patient complexity through focused exploration of the term.

Results indicated that a number of environmental, sociological, psychological, behavioural, physical and organisational factors needed to be included. This, in turn, showed that an existing taxonomy did not contain the relevant items. Consequently, amendments were made and a new instrument developed.

Conclusion GCM is a suitable consensus method for use in nursing theory and developing instruments. It proved successful in achieving consensus with no loss of participants’ views.

Implications for practice GCM is a suitable method for nurses to use in research or practice development activities as it is based on a facilitative and engagement-led approach.