Multifinality, equifinality, and fanning: Developmental concepts and statistical implications

Multifinality, equifinality, and fanning are important developmental concepts that emphasize understanding interindividual variability in trajectories over time. However, each concept implies that there are points in a developmental window where interindividual variability is more limited. We illustrate the multifinality concept under manipulations of variance in starting points, using both normal and zero-inflated simulated data. Results indicate that standardized estimates and effect sizes are inflated when predicting components of growth models with limited interindividual variance, which could lead to overinterpretation of the practical importance of findings. Conceptual implications are considered and recommendations are provided for evaluating developmental changes in common situations that researchers may encounter.