Data gathered at each session: coded at beginning of each session to determine a family s progress toward mastery criteria. Pcit is not time-limited number of sessions vary. Sensitivity to developmental concerns: behaviour problems peak around 3 and decline during preschool years. Pcit must have keen sense of each child s developmental capabilities. Special space and equipment: observation room through one-way mirror using hearing aid device, while family in adjoining playroom. Should not include furniture that can tip over, working sinks, plants, computers, inappropriate toys. Ideal playroom = sparsely furnished, including 1 table and chairs, has covered light switches, constructional/creative toys. 3rd room = time-out room, adjoining first 2 (small, has 2 small unbreakable windows in each door so can see them, lighted/ventilated, no furniture or objects, no electrical outlets) Pdi provide consistent consequences for non-compliance (so can t escape demands: targets negative attention-seeking and non-compliance.