Objective.\p=m-\To determine the independent effect of socioeconomic, organiza- tional, and professional liability factors on the odds of vaginal birth after cesarean delivery (VBAC) while controlling for important clinical factors. Design.\p=m-\Aretrospective study of 1989 New York State vital statistics data, supplemented with additional information on county- and hospital-specific vari- ables. Using multiple logistic regression analysis, odds ratios (ORs) and 95% con- fidence intervals (CIs) were derived for 15 independent variables. Setting.\p=m-\Birthsoccurring in 104 New York State hospitals. Data Set.\p=m-\Atotal of 13944 births occurring to New York State residents with a history of cesarean delivery of which 3068 (22%) were vaginal deliveries. Results.\p=m-\Theodds of VBAC increased with maternal education. The ORs were 1.15 (95% CI, 0.99 to 1.34) for 12 years of education; 1.36 (95% CI, 1.16 to 1.60) for 13 to 15 years; 1.59 (95% CI, 1.32 to 1.93) for 16 years, and 2.00 (95% CI, 1.64 to 2.45) for 17 years or more. The ORs also increased with the level of care pro- vided by the hospital; they were 1.55 (95% CI, 1.34 to 1.81) and 1.30 (95% CI, 1.18 to 1.44) for hospitals with intensive and intermediate neonatal care facilities, respectively. The ORs were 1.15 (95% CI, 1.02 to 1.30) for health maintenance or- ganization participants and 0.77 (95% CI, 0.63 to 0.94) for women giving birth in government hospitals. The ORs of VBAC for African-American and Hispanic mothers were 0.80 (95% Cl, 0.70 to 0.93) and 0.61 (95% CI, 0.51 to 0.73), respec- tively. The ORs for a $5000 increase in physician's yearly malpractice premium and the hospital's paid loss due to malpractice claim settlements were 0.98 (95% CI, 0.97 to 0.99) and 1.01 (95% CI, 0.99 to 1.03), respectively. Conclusions.\p=m-\Inaddition to clinical factors, a mother's level of education and ethnicity and specific characteristics of the hospital in which she delivers affect the odds of a vaginal delivery after a previous cesarean delivery. From our analysis, we cannot conclude that professional liability factors affected VBAC rates. (JAMA. 1994;272:524-529)