Q-Sat AI: Machine Learning-Based Decision Support for Data Saturation in Qualitative Studies
Qualitative research often relies on subjective judgments of data saturation to determine sample size, leading to methodological inconsistency and compromised rigor. To address this, we propose the first machine learning–based decision support model for sample size determination, pioneering the application of ensemble learning methods—including XGBoost and Random Forest—to quantitatively model the data saturation process. The model integrates ten key study design parameters, undergoes rigorous preprocessing and outlier removal, and achieves an R² of 0.85, effectively capturing nonlinear relationships in sampling dynamics. Feature importance analysis empirically validates foundational theoretical assumptions—such as the influence of study type and informational power—advancing standardization in qualitative methodology. The model has been implemented as an open-source web tool for researchers and reviewers, substantially enhancing transparency, reproducibility, and methodological rigor in sample size justification.