MacBean V, et al. - An aggregate of one hundred sixty-eight infants (median (IQR) gestational age 33 (31-34) weeks) were selected in the neonatal period from consecutive births in a tertiary neonatal unit to test the hypothesis that cluster analysis would identify discrete groups of prematurely born infants with differing respiratory outcomes during infancy. They used the baseline characteristics of the infants to classify them into hierarchical agglomerative clusters. It was observed in the findings that readily available clinical data allowed classification of prematurely born infants into one of three distinct groups with differing subsequent respiratory morbidity in infancy.