Multiplicity in rehabilitation research: a quantitative assessment.

Recent studies indicate that rehabilitation researchers frequently include multiple tests of significance in their investigations. This study examined the possibility that the Type I error rate in rehabilitation research is inflated due to the inappropriate analysis of data from multiple significance tests. The incidence of Type I error was computed for a sample of rehabilitation research. The results revealed a Type I error assumed level of 5% (p less than .05). The argument is made that methods to determine the rate of Type I error should be routinely used in rehabilitation research.