in 1998, congress mandated an intensive study of the effectiveness of head start, the "head start impact study," which studied a target population of 5,000 3- and 4-year-old children. the study measured head start's effectiveness as compared to other forms of community support and educational intervention, as opposed to comparing head start to a nonintervention alternative. head start impact study first year findings were released in june 2005. study participants were assigned to either head start or other parent–selected community resources for one year. 60% of the children in the control group were placed in other preschools. the first report showed consistent small to moderate advantages to 3-year-old children including pre-reading, pre-vocabulary and parent reports of children's literacy skills. no significant impacts were found for oral comprehension, phonological awareness, or early mathematics skills for either age group. fewer positive benefits were found for 4-year-olds. the benefits improved with early participation and varied across racial and ethnic groups. these analyses did not assess the benefits' durability.