Care Practices and Bronchopulmonary Dysplasia Debate
1 Bethesda, MD
2 Boston, MA
In Reply.
We appreciate the opportunity to clarify the issues raised by Barry et al. We tested the significance of the differences among centers in the incidence of chronic lung disease, adjusted for sex, race, and birth weight, by computing two multiple logistic regression models. The first model included only sex, race, and birth weight as independent variables. The second model additionally included seven dummy variables representing the eight centers. Twice the difference in the log likelihoods in the two models has a
2 distribution with 7 df under the null hypothesis of no center differences.




