Alejandro Sanfeliciano, Carlos Hurtado-Martínez, Luis Botella and Luis Ángel Saúl introduce the Similarity Self/Ideal Index (SSI) in Mathematics, a proposal for modelling current–ideal self similarity within Personal Construct Psychology.
Inspired by Tversky’s feature-based similarity model, the index considers shared and distinctive attributes in the two self-representations. Its formulation takes account of the direction and magnitude of evaluations on personal constructs.
SSI offers an alternative to comparisons based solely on correlations and examines congruence between how people see themselves and how they wish to be, preserving their own dimensions of meaning.
The article develops the index’s mathematical foundations and properties within WimpGrid. It provides a tool for investigating self-perception, aspirations and psychological well-being; further validation and research on sensitivity to change remain necessary.
Sanfeliciano, A., Hurtado-Martínez, C., Botella, L., & Saúl, L. A. (2025). Similarity Self/Ideal Index (SSI): A Feature-Based Approach to Modeling Psychological Well-Being. Mathematics, 13(24), 3954.