People with different ideological identities differ in their values, personality, affect, and psychological motivations. These differences are observed on measures of practical and clinical importance and these differences are the central node tying together theories about the psychology of political ideology; however, they rest on a critical untested assumption: The measures are invariant across ideological groups. Here, we test this assumption across 28 constructs in data from the United States and the Netherlands. Measures are not invariant across ideological divisions. At the same time, estimates of ideological similarities and differences are largely similar before and after correcting for measurement noninvariance. This may give us increased confidence in the results from this research area, while simultaneously highlighting that some instance of noninvariance did change conclusions and that individual items are not always comparable across political groups.

具有不同意识形态认同的人在价值观，个性，情感和心理动机上各不相同。这些差异在实践和临床上具有重要意义，这些差异是将政治意识形态心理学理论联系在一起的中心节点。然而，它们基于一个未经检验的关键假设：这些度量在意识形态群体之间是不变的。在这里，我们在来自美国和荷兰的数据中的28个构造上测试了该假设。跨意识形态划分的度量并非不变。同时，在对测量不变性进行校正之前和之后，对意识形态相似性和差异的估计在很大程度上相似。这可以使我们对这个研究领域的结果更有信心，