PURPOSE: After an initial management plan has been determined, some form of systematic reassessment is frequently used to guide decision making in ongoing conservative management of patients with musculoskeletal symptoms. In order for reassessment to be informative, the parameter being assessed should be responsive to small changes in the patient's condition and be able to predict treatment outcomes. Functional outcome measures are often too insensitive to provide guidance in moment-to-moment decision making, while changes in impairments may have only a limited relationship with treatment goals. DESCRIPTION: A wide variety of parameters have been advocated to be reassessed at various time intervals. Protocols for repeating assessments prior to the actual application of interventions including assessing changes in impairments during movement direction tests, treatment direction tests, and trial treatments have been suggested as means to inform clinical decision making. The most common use of reassessments is perhaps to evaluate changes following interventions. Changes in impairments such as joint position and mobility; muscle strength, length and response; pain intensity and location; quantity and quality of active movements and functional activities have been advocated to indicate effectiveness following interventions. A review of the evidence provides limited support for the use of some forms of movement direction tests and treatment direction tests. Reassessments of changes in active range of movement or centralization of pain following an intervention appear to be reasonable indicators of treatment effectiveness. Changes in pain intensity, joint position or muscular response are less useful while there is conflicting evidence on the use of changes in segmental stiffness. Although psychosocial factors are predictors of patient outcomes, little mention is made in the literature of the use of changes in psychosocial parameters to inform ongoing decision making or predict treatment outcomes. SUMMARY OF USE: The evidence suggests that a methodical approach that considers change in patient impairments can be a useful guide for decision making during ongoing patient management, but only when the impairment being reassessed can be directly linked to functional goals. IMPORTANCE TO MEMBERS: The author suggests that it may not be necessary to establish either a cause and effect or a physiological relationship between the intervention and the change being reassessed. Rather, the usefulness of a reassessment relies simply on how well the change being reassessed predicts that individual patient's ability to achieve their goals.