Studying determinants of length of hospital stay.

Clinicians are accustomed to focusing on individual patients. However, when studying how long their patients stay in the hospital, the focus must widen. Length of stay summarizes the performance of the entire, exceedingly complex, NICU system. Ordinary statistical methods for modeling patient outcomes assume that what happens to one patient is unrelated to what happens to another. However, patients in the same NICU are exposed to similar hospital practices, so patient outcomes may be correlated. Length of stay data must be analyzed by methods that account for possibly correlated outcomes. In addition, to improve patient care and outcomes, predictive models must include determinants clinicians can influence. Such variables describe care process exposures, available beds, demand for beds, and staffing levels.