The research was considered to offer strong support or evidence for a conclusion if (1) there were several solid experimental studies or quasi-experimental studies that supported it; and/or (2) there were a significant number of correlational studies that supported it involving advanced statistical approaches such as regression analysis; and (3) there were very few, if any, studies that cast doubt upon the conclusion. In other words, there needed to be an unequivocal pattern of support for the conclusion on the basis of solid quantitative research. The research was considered to offer moderate support or evidence for a conclusion if it did not meet the criteria for strong support, but (1) there were one or more solid experimental studies or quasi-experimental studies that supported it; and/or (2) there were more than several correlational studies that supported it involving advanced statistical approaches; (3) there were few studies that cast doubt upon the response; and (4) in borderline cases, especially if there was disagreement among studies, there were descriptive studies present that made it more plausible that certain correlations were based upon a true causal relationship. In other words, there needed to be a clear pattern of support for the conclusion on the basis of solid quantitative research. The research was considered to offer limited support or evidence for a conclusion if it did not meet the criteria for moderate support, but (1) there was at least one solid experimental study or quasi-experimental study that supported it; and/or (2) there were several correlational studies that supported it involving advanced statistical approaches; (3) there were a preponderance of descriptive studies that supported it, and (4) there was considerably weaker evidence in support of any conflicting conclusion. If the research for any conclusion did not at least meet the standard of providing limited support, then it was regarded as being inconclusive. This could be the case both when only one or two studies supported a conclusion and when there were not significantly more studies that support one conclusion than support one or more opposing conclusions.