Three recent research reports by Topping and Trickey (2007a; 2007b), by Fair and colleagues (2015), and by Gorard, Siddiqui and Huat See (2015) have produced data that support the conclusion that a Philosophy for Children (P4C) program of one-hour-per-week structured discussions has a marked positive impact on students. This article presents data from a follow up study done three years after the completion of the study reported in Fair et al. (2015). The data show that the positive gains in scores on the Cognitive Abilities Test (CogAT in the USA and CAT in the UK) were still present and had not faded after three years. Given the strength of these confirmations of the positive durable impact of the P4C program of structured discussions and given the relatively low cost of implementing the P4C program, it is recommended that it become a standard part of the school curriculum.