Cross-Model Consistency of Feature Importance in Electrospinning: Separating Robust from Model-Dependent Features

TL;DR

This study evaluates the consistency of feature importance across multiple machine learning models in electrospinning, revealing that some parameters are robustly influential while others are highly model-dependent, emphasizing the need for cross-model validation.

Contribution

It systematically compares feature importance across 21 ML models using SHAP values, highlighting the variability and robustness of parameter rankings in electrospinning.

Findings

Solution concentration is the most robust feature across models.

Flow rate and voltage show high variability in importance rankings.

Predictive accuracy does not guarantee interpretive reliability.

Abstract

Electrospinning is a highly sensitive fabrication process in which small variations in operating parameters can significantly influence fiber morphology and material performance. Machine learning (ML) methods are increasingly employed to model these process-structure relationships and to identify the relative importance of processing variables. However, most existing studies rely on a single ML model, implicitly assuming that the resulting feature importance is robust and reproducible. In this study, the consistency of feature importance across multiple ML model families was systematically evaluated using a curated dataset of 96 polyvinyl alcohol (PVA) electrospinning experiments. Twenty-one ML models representing linear, tree-based, kernel-based, neural network, and instance-based approaches were trained and compared. To provide a unified interpretability framework, SHAP (SHapley Additive exPlanations) values were used to calculate feature importance consistently across all models. A rank-based statistical analysis was then performed to quantify inter-model agreement and assess the robustness of parameter rankings. The results demonstrate that predictive performance and interpretive reliability are fundamentally distinct properties. Although several models achieved comparable predictive accuracy, substantial differences were observed in their feature importance rankings. Solution concentration emerged as the most robust and consistently influential parameter (variability = 0), whereas flow rate and applied voltage exhibited high ranking variability (variability > 0.9), indicating strong model dependence. These findings suggest that feature importance derived from a single ML model may be unreliable, particularly for small experimental datasets, and highlight the importance of cross-model validation for achieving trustworthy interpretation in ML-assisted electrospinning research.