In this sample, paternal stimulation showed good internal consistency (α = 0.77). The total number of stimulation activities was categorized into 3 groups: high engagement (5–6 activities), moderate engagement (1–4 activities), or no engagement (0 activities). This classification was motivated by a primary interest in examining differences among fathers who engaged in none of the stimulation activities, as compared with those who engaged in some or all of the activities.