A third potential limitation is that the present study did not assess independently the relative importance or power of each individual risk factor. There is some evidence that different risks have varying effects on outcomes (e.g., Ackerman etal.,1999). Therefore investigating risk accumulation alongside risk specificity would be an appropriate approach which further research could investigate. Nonetheless, this does not undermine the use of a cumulative risk model, which unlike specificity models, is able to account for the natural co-variation of risks and offer more stable measurements. Cumulative models are also found consistently to account for more variance in behavioral outcomes than any single factor (Flouri & Kallis, 2007).