Overall prognosis as the primary criterion of outcome in a clinical trial

In a randomized trial on premature infants, with follow-up to 1 year of age only, the goal is to identify which one among the compared strategies of intervention affords the best outcome throughout life. This requires the assessment of lifetime prognosis at the end of follow-up as the primary criterion of outcome. Moreover, with the treatments potentially influencing a variety of organ systems, it is necessary to combine their separate prospects into an overall prognosis as a basis for identifying the preferable mode of intervention. The development of the scheme of rating overall prognosis posed considerable challenges, in theory as well as in application.