Knowledge of the force history is crucial for evaluating the performance of structures and mechanical components. Since direct force measurement is impossible or impractical in many cases, alternative methods must be used. For an elastic body, a method has been developed employing the equations of motion which provide an expression for the applied force as a sum of weighted accelerations (SWA). Since this method is relatively new, its sensitivity to errors caused by inaccurate accelerometer data, or poor gauge placement, must be characterized and well understood for simple structures before the SWA can be applied to large, complex structures. In this paper, these error sources are investigated independently through numerical simulations of a simple beam. The conclusion reached is that the predictive capability of the SWA is not significantly affected by small errors in the accelerometer data or non-Ideal gauge placement.