Age at start as a correlate of intervention effectiveness

Age at start as a correlate of intervention effectiveness Psychology in the Schools Volume 24, January 1987 AGE AT START AS A CORRELATE OF INTERVENTION EFFECTIVENESS’ MARGO A. MASTROPIERI~ Purdue University This investigation examined the “earlier one starts an intervention, the better” hypothesis for handicapped preschoolers. Posttest performances of handicapped preschoolers on the Bayley Mental Development Index (MDI) and the Bayley Psychomotor Development Index (PDI) were evaluat