Participation bias among suicidal adults in a randomized controlled trial

Although individuals who attempt suicide have poor compliance rates with treatment recommendations, the nature and degree of participation bias in clinical treatment research among these individuals is virtually unknown. The purpose of this study was to examine participation bias by comparing the demographic and diagnostic characteristics of adult suicide attempters who participated in a randomized controlled trial to a sample of nonparticipants. Results indicated that males and individuals with a diagnosis of substance abuse or dependence were more likely to be participants in the randomized controlled trial. The implications of these findings for suicide intervention research are discussed.     

Children's use of the bearing angle in interceptive actions

The authors investigated the effect of ball velocity and walking direction on children's adherence to the constant bearing angle (CBA) strategy. Children (N = 20) approached a moving ball to manually intercept it at a predefined target area. Results revealed that 10- to 12-year-olds adhered more than 5- to 7-year-olds to the CBA strategy. Younger children deviated more than older children from smaller angles of approach and lower ball velocities. The present findings suggest that younger children have difficulty adjusting to task requirements because they fail to couple walking velocity with ball velocity. The improvement seen with increasing age suggests that compliance with the CBA strategy may be attributed to older children's enhanced coincidence anticipation.