Stochastic modeling of NCO personnel structure in South Korea army: DTMC and simulation-based analysis

Abstract

This study analyzes the long-term structure of the South Korean Army’s non-commissioned officer (NCO) personnel using a stochastic modeling approach. Persistently low recruitment rates and rising discharge rates pose challenges to maintaining the NCO force, and with an impending demographic cliff expected after 2035, examining the personnel structure has become increasingly valuable. Using 2016–2020 data, a Discrete-Time Markov Chain (DTMC) model was developed to estimate steady-state rank distributions. To address limitations in the DTMC’s applicability to real-world conditions, a simulation model was constructed incorporating minimum service periods and mandatory retirement ages. Comparative analysis reveals that mid- and senior-level ranks are disproportionately affected by declining NCO intake, and that targeted improvements in Sergeant First Class retention yield the most significant impact on overall force size. These findings suggest that strategic personnel planning should prioritize mid-level NCOs to sustain operational readiness. The study offers a pioneering quantitative framework for evaluating future personnel policies under demographic and structural constraints.