The importance of ongoing refinement of measurement tools is illustrated by describing the methodology for further development of an Interpersonal Conflict scale. A third dimension, that of Sexual Need, was defined and added to the original sub-scales of Interaction Need and Emotional Need. Thirty-one Sexual Need items were formulated and incorporated into the original scale and the revised list was submitted to a sample of 212 subjects. The methods used to study content and face validity are discussed; factor analytic techniques for assessing construct validity and reliability of the Sexual Need dimension are presented. Six alternate forms of approximately equal reliability were developed for repeated measurements over time. The overall analyses are discussed within a framework of the relationship between fulfillment of psychosocial needs and marital conflict.