Abstract

"Beginning with the concept of evaluation, several approaches to outcomes or results evaluation are reviewed: clinical measurement, quality of life, and willing-ness to pay. Clinical measurement is the simplest and most available, but is limited when 1) establishing the effects of comparable interventions for different pathologies, 2) detecting different degrees of improvement achieved, and 3) identifying the result of interventions measured in variables associated to patient lifestyle and quality of life. When the health services measure the quality of life, the results of the intervention are subjectively evaluated by the patient with respect to wellbeing and satisfaction. The measurement of quality of life can be considered specific, generic or based on utility to the extent that it is based on the estimation of a specific variable such as the perception of pain, the patient?s general state of health, or the estimation of uses normative values based in preference studies at the population level, respecti-vely. The method of willingness to pay values the life according to the amount that individuals are willing to pay for a change that reduces the possibility of sickness and death, assuming that patients prefer those procedures to which they assigned the highest value. This evaluation of outcomes incorporates more than just strictly health considerations and expresses results in monetary terms, which facilitates cost-beneft analysis. Additionally, the results can be measured at a macro, national level; at a meso-scale, referring to the health systems of a determined territory; and at the level of the users. Finally, evaluating results or outcomes in order to determine the intervention?s effectiveness should be associated to its cost and must be studied using research designs that guarantee that the changes have sufficient time to appear and are observables. The monitoring period should be sufficiently long to explain the different results observed in the studies."