To identify the characteristics of early intervention programs most predictive of growth in participants' competencies, a comparison was made of the effects of three different Iowa Head Start programs on teachers, mothers, and children. Three agencies with home-based, three with center-based, and three with combination programs from rural areas and small communities participated in the study. Measures of cognitive development of the children, home stimulation provided by the mothers, teacher attitudes toward Head Start parents, and demographic measures were obtained near the beginning and end of a program year for 70 families. In contrast to mothers in home-based and center-based programs, mothers in combination programs decreased the stimulation of their children over the program year. Mothers in home-based programs reported more involvement in Head Start program activities than did mothers in other programs. Teachers in combination and center-based programs reported receiving less training for home visiting than did teachers in home-based programs. Teachers with more experience in Head Start and teachers with more formal education unrelated to early childhood education also expressed stronger negative attitudes toward parents than did teachers with less education and experience. Implications for teacher training and evaluation in combination, home-based, and center-based early intervention programs are discussed. (Author/RH)