Disclosed are embodiments of an improved production planning method that avoids or limits early builds. The method comprises running a conventional production planning program using standard inputs (e.g., date effective yields). The outputs of the program (e.g., a plan including planned inventory overstocks at given times) are evaluated to determine if the program plans an early build and if the planned early build may have been triggered by a predicted decrease in yield. If an early build is planned and if a correlation exists between the decrease in yield and the early build, then, optionally, new constraints are added into the program and the program is re-run so that the early build is either avoided or limited to that of the proper yield. Thus, the method can be used to reduce early builds due to an incorrect, nominally higher, yield without requiring the user to provide any special additional input data.