Construct Equivalence, Probe Questions and Comparability of the Left-Right Scale in a Cross-National Perspective

Equivalence in survey design and implementation is one of the core issues in cross-national survey research. Construct equivalence dealing with the theoretical validity of concepts measured by survey questions and item batteries is a pre-requisite for meaningful cross-national analyses and comparisons where respondents are socialized in different political, social and cultural contexts. Thus the same interpretation of concepts cannot be taken for granted.

Our paper is about construct equivalence of the left-right scale in a cross-national perspective. The left-right scale is a standard question used to measure ideological orientation in a minimalist way. However, the theoretical concepts related to left and right might differ across countries. Variation in the understanding of left and of right is a comparability issue if the variation is systematic in different contexts.

To test the understanding of the left-right scale in cross-national context, we have asked about respondents’ individual associations with the terms left and right by using open-ended questions in an experimental online survey fielded in Canada, Denmark, Germany, Hungary, Spain, and the U.S. in 2011. We have coded open-ended answers using an extensive coding scheme and we have tested whether the similar empirical relations and ideological dimensions can be found across countries. Similarity in this respect is interpreted as evidence supporting the hypothesis of measurement equivalence.

In a first step of cross-national analyses we concentrate on the ranking of frequencies of individual answers and on the link between left-right self-placement and open-ended questions. Results of this analysis show that respondents from different countries do not have the same ideas in mind when considering what left and what right mean for them. These results challenge the comparison error of the left-right scale because responses have different meanings in different cultural contexts and conclusions based on such comparisons might be wrong.