Preschool disruptive behavior problems were investigated in a meta-analysis of 26 studies using categorical and/or dimensional approaches to assessment. The review sought to distinguish early disruptiveness from normative preschool conduct by showing that, irrespective of assessment methodology: (a) disruptiveness can be adequately measured in the preschool years; (b) early disruptiveness is stable over time; and (c) disruptive children referred for clinical services in the preschool years can be distinguished from non-referred peers. Results indicated that: categorical and dimensional approaches to measurement of early disruptiveness provide comparable data (effect size d=2.29); both approaches yield comparable estimates of the stability of preschool disruptive behavior over time (categorical approach: d=1.15; dimensional approach: d=0.84); and both approaches discriminate between referred and non-referred preschoolers (d=1.05 and d=.95). Limitations of the existing literature and of this analysis are discussed, as are suggestions for future research.