Conducting ANOVA Trend Analyses Using Polynomial Contrasts.

When analysis of variance (ANOVA) or linear regression is used, results may only indicate statistical significance. This statistical significance tells the researcher very little about the data being analyzed. Additional analyses need to be used to extract all the possible information obtained from a study. While a priori and post hoc comparisons can be done with qualitative data, trend analysis is most often recommended for studies with quantitative variables with fixed intervals or effects. This paper illustrates the use of trend analysis using ANOVA and multiple regression using heuristic examples. Limitations to trend analyses are also discussed. While trend analyses can be hand calculated for simple one-way ANOVAs, it is easier and more efficient to use statistical programs such as the Statistical Package for the Social Sciences (SPSS) for more complex designs such as factorials. Three appendixes illustrate trend analysis using ANOVA, regression, and multiple analysis of variance in the SPSS. (Contains 2 figures, 6 tables, and 25 references.) (Author/SLD)