Abstract: Accurate determination of nursing levels for disabled elderly constitutes a critical issue in long-term care systems. Grounded in grey systems theory, this paper proposes a nursing level discriminative method that integrates nursing task decomposition with discrete grey number operations. Drawing upon Work Breakdown Structure from project management, disabled elderly care is decomposed into eight fundamental nursing tasks. Nursing time data are collected through three consecutive days of observation, discrete grey numbers are constructed, and grey possibility functions are designed for level determination. Case analysis involving five disabled elderly from three nursing institutions successfully assigns each case to the corresponding nursing level. The study reveals that possibility function values for adjacent nursing levels are relatively close for certain elderly, indicating their position in boundary regions and suggesting the need for enhanced monitoring and timely level adjustment. The proposed method effectively handles uncertainty in nursing time, provides definitive level determination while identifying boundary cases, and offers decision support for dynamic monitoring and care resource allocation.

Key words: Grey discriminative, Disabled elderly, Nursing task decomposition, Discrete grey number, Nursing level