Response to von Eye and Wiedermann’s commentary Strengthening arguments based on scale levels?

摘要

In a thought provoking commentary, von Eye and Wiedermann (2018) discussed the choice of statistical method in relation to scale level and then gave as an example the study of longitudinal stability of aggression based on a cross-tabulation of aggression at age 10 against aggression at age 13. Aggression was measured by seven-graded scales (1-7) and a 7 x 7 table was presented. The table was taken from my article in the Journal for Person-Oriented Research (Bergman, 2017). There a Pearson correlation of r = 0.43 was reported, indicating a moderate stability of aggression. The main statement I made was that this correlation carries information about the stability at a group level but that it does not inform about individual stability. Von Eye and Wiedermann seem to agree with the second part of this statement but point out that the interpretation of r is not straightforward –among other things it depends on the assumptions you make about the scale level of the measures of aggression. Analyzing the relationship with methods assuming nominal scale level and ordinal scale level they find that the method for ordinal analysis they used indicated no stability in aggression - in contrast to the findings obtained using methods assuming nominal or interval scale level. They also made the important point that, within an ordinal scale level framework, there exist methods for examining person-oriented statements in a more formal way than the simple counts presented in my article and that the toolbox of configural frequency analysis (von Eye, 2002) could be used for that purpose.