Of the 731 families who initially participated, 659 (90%) were available at the 1-year follow-up, 619 (85%) participated at the 2-year follow-up when children were between age 4 and 4 years 11 months, 621 (85%) participated at the 3-year follow-up when children were between age 5 and 5 years 11 months, and 566 (77%) participated in the 5.5-year follow-up when children were between 7 years 4 months and 8 years 5 months. At ages 3, 4, 5, and 7.5, selective attrition analyses revealed no significant differences relevant to project site; children’s race, ethnicity, or gender; levels of maternal depression; or parent-reported children’s disruptive problem behavior. Furthermore, minimal differences were found in the number of participants who were not retained in the control versus the intervention groups at age 3 (n= 40 and n= 32, respectively),age 4 (n= 58 and n= 53, respectively), age 5 (n= 48 and n= 62, respectively), and age 7.5(n= 74and n = 91, respectively). For teacher ratings of child oppositional problems at age 7, only 314 reports were available, primarily because of difficulties in obtaining cooperation
