Evaluating the accuracy of time phasing in missile and munition development using continuous distribution functions

Purpose This paper evaluates the empirical validity of heuristic time-phasing rules in missile and munition defense acquisition and proposes data-driven alternatives using continuous distribution functions. Design/methodology/approach Using normalized cost data from 21 US Department of Defense missile and munition programs, this study fits Rayleigh, Weibull and Beta distributions to actual expenditure profiles and develops regression models to estimate distribution parameters from basic program descriptors. Findings The 60/40 rule, while close to average, shows significant variance across programs, limiting its reliability for budget planning. The Weibull distribution consistently outperformed alternatives across goodness-of-fit measures and remained stable under parameter estimation. Practical implications Integrating regression-informed Weibull models into early-stage acquisition planning can enhance the alignment of funding profiles with actual execution, improve the realism of cost projections and mitigate risk from mismatched phasing assumptions. Originality/value This study is the first to empirically test continuous time-phasing models on missile and munition RDT&E programs, providing a tailored, defensible alternative to generic S-curve heuristics.