Same same OR Different?

With this project, I aim to investigate combinations of characteristics within people. While trying to determine the universal building blocks of personality, it seems that researchers have focused on similarities rather than differences; In both regards: Similarities between people, as well as between personality characteristics. Accumulating research is now challenging prominent conceptualizations of personality and with it the method of aggregation. By aggregating item responses into sum scores and individuals into groups, relevant differences between them might have been overlooked. Our goal is to offer new levels of explanation to allow the integration of findings. To this end, we will cluster people by their item-response-patterns. We will investigate the heterogeneity of these clusters, and assess if similar levels (i.e. sums scores) on the five domains of the five factor model can reduce heterogeneity by accounting for similarities between item-response-patterns. Next to this confirmatory part, we aim to largely explore the combinations of characteristics within people by describing the possible cluster solutions. We will split our sample into three samples to be able to test any findings the result from exploration. Personality characteristics will be operationalized as the 263 unique items (of the full 300 version) of the IPIP-NEO, also called personality "nuances". René Mõttus research line has examined these nuances intensively and found, among other features, rank-order stability, cross-rater agreement, heritability. He has suggests them to be included in the personality trait hierarchy.