males with family history. That being said, purpose of the meta-analysis (an evaluation of experimental data) was to find if there is an general difference in P3 amplitude between subjects with a family history of alcoholism and those with no family history, taking all variables into account.
             The system of meta-analysis used by the authors of this article is very precise and thorough. In effect, the data from relevant studies was quantitatively "averaged" by standardizing the varied range of experimental outcomes. Thus, the authors first had to find studies that would be appropriate their research. This simply involved searching for pertinent literature on the computer, and contacting researchers considered to be experts in this area. Articles from the computer searches (searches used such phrases as "P300," "late positive component," and "alcoholism risk) were selected for analysis if they pertained to the study of non-alcoholic males with and without a family history of alcoholism. The P3 event-related potentials of these groups were measured through the subjects' participation in attention-related tasks involving the differentiation of stimuli, or focusing on a specific stimulus while ignoring all distraction. Other useful studies selected from reference citations (bibliographies), along with the relevant contributions of their contacts, were consolidated with the studies chosen from the computer search, resulting in 30 studies in all. Next, in order to standardize the findings of the compiled studies, all variables, or moderators, must be identified and statistically taken into consideration. The moderators identified for this particular analysis were factors that may effect the degree of differentiation in P3 amplitude. Previous research on the subject of P300 and alcoholism has suggested t
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