This article presents the methodological bases that guide the development of instruments to measure psychosocial variables. It describes the theoretical, empirical or experimental and analytical and exemplifies the theoretical steps through the experience of developing an instrument to measure power-lessness as a nursing diagnosis. The most difficult procedures for developing instruments to are the theoretical steps. They require the development of theoretical sensitivity as a continuous going forward and backward between concrete and abstract issues; they also require the development of tolerance towards ambiguity, but without abandoning the examination of evidences.
Nursing diagnosis; Psychometrics; Methodology