Power analyses focus on estimating a sample size large enough to detect "true" effects, thereby avoiding Type II errors. Sample size estimates were obtained for intervention contrasts. Necessary sample sizes were assessed via sample size and power equations for normally distributed outcomes. Effect-sizes and variance components were based on preliminary studies, and power was set at 0.80 for all estimates. Power was estimated using the Optimal Design software program. The investigators anticipate intervention effects relative to the neutral control condition on drinking to be in the range of delta =.30-.40). Based on the proposed sample size of 500 (~PNF not included in H1a and H1b), given five assessment points, the investigators anticipate the ability to detect main effects of intervention contrasts with power=.80. Considering maximum anticipated attrition rates of 20% the investigators will have .80 power to detect effects sizes of delta = .28 and greater.