This research shows that a model that concurrently determines product, production, and capacity can provide better results than a model that makes these decisions sequentially. Three versions of a life-cycle complete concurrent model and corresponding sequential model that solve product, production, and capacity planning problems are mathematically formulated and compared through an hypothetical example. All versions of the concurrent and sequential models consider three types of work centers and corresponding types of capital budgeting projects. Each version of the concurrent and sequential models considers a specific type of capital budgeting project. These are: (1) projects that may be partially accepted with no upper limit, (2) projects that may be partially accepted with an upper limit of one, and (3) projects restricted to values of zero and one. An hypothetical example spanning twelve fiscal periods that included five products, two product sub-groups, one pre-production/post-support project, three production projects, and one support project was developed to enable comparison of the models. Nine comparisons between each of the three versions of the concurrent and sequential models were conducted resulting in a total of 27 comparisons. Comparisons of the models required the development of five computer programs. Four of these programs provided Mathematical Programming System (MPS) formatted mixed integer linear programs (MIP) that were solved using the LINDO/386 optimization program. The fifth program read output from LINDO/386 and provided the future worth of the sequential model. Results obtained from tests of the concurrent and sequential models were compared based upon future worth, capital budgeting projects funded, products funded, production and inventory quantities, and regular and overtime labor levels. For every combination of product sub-group demand and capital budgeting constraint type, the concurrent model always provided the highest future worth. In addition, while both models funded the same set of products, the concurrent model provided more level labor, production and inventory quantities, and support for products. Following these comparisons, it was concluded that, for any capital budgeting constraint type and product sub-group demand, a concurrent model can provide better planning results than a sequential model. / Ph. D.