The FSS was developed by a formal consensus process of health professionals from 11 institutions within and outside the research network including pediatricians, pediatric neurologists, pediatric developmental psychologists, pediatric physiatrists, pediatric nurses, pediatric intensivists, and pediatric respiratory therapists. A prior, single institution pilot study had demonstrated the utility of using the primary nurse as a suitable observer for functional status, the potential of a simple scale to accurately reflect functional status as measured by adaptive behavior, and the potential to correctly categorize patients by functional status. The pilot study showed very good inter-rater reliability between two data collectors, and supported the use of adaptive behavior to establish external validity. Domains of functioning selected during the consensus process included mental status, sensory functioning, communication, motor functioning, feeding, and respiratory status (Table 1). Functional status for each domain was categorized from normal (1 ) to very severe dysfunction (5 (link)). FSS scores ranged from 6 to 30. The definitions of the domain cells are shown in the Appendix.