Use of variance from clinical paths: coming of age.

The introduction of critical paths, generically referred to as clinical paths, into the planning, delivery, documentation, and evaluation of patient care provided a tangible method for clinical experts to identify elements they collaboratively perceived to represent a stable, predictable, patient-care episode. Variance is the difference between the planned, stable process for a homogeneous group of patients and the actual, individual, unique care delivery experience. Building the formal use of both task (intervention) and outcome variance into a clinical path approach is fundamental to the individualization of care given concurrently and the creation of an aggregate database for retrospective evaluation, continuous quality improvement, and research. As clinical paths have become more accepted and sophisticated over the last decade, the use of variance also has evolved, albeit one step behind. Variance from length of stay and task (intervention)/resource still predominates clinical path application and literature. Real progress in healthcare practice will not be made until variances from measurable intermediate goals and patient responses and outcomes are combined with other data and transformed into knowledge. The use of variance, from past to future stages, provides a mirror of the transformation of healthcare delivery in the United States and other countries.