Differences (with 95% confidence interval) in adjusted probabilities of survival after diagnosis of CML between patients receiving HLA-identical sibling bone marrow transplants versus hydroxyurea or interferon. Differences were calculated as probability of survival with transplant minus probability of survival with nontransplant treatment. A negative difference indicates a survival disadvantage for transplant; a positive difference indicates an advantage for transplants. A 95% confidence interval that does not include zero indicates a statistically significant difference.