A new process analysis and design tool was developed The analysis tool consists of a systematic algorithm for analyzing a block diagram representation of a process flowsheet and identifying different paths between a given input and output variable, Transfer function representations of different paths are calculated to determine the contribution of each path to the overall attenuation characteristics of the process. To improve these attenuation characteristics, the paths that contribute the most to the overall variability mast be identified and addressed. The design fool consists of a set of guidelines that the engineer can nse to develop alternate process designs or control strategies to eliminate these identified paths, reduce their contribution to overall variability, ol negate their effects by adding new paths. Although the ingenuity of the design engineer is critical, this tool provides the engineer with a means to identify problems irt a process design, to help develop design alternatives, and a quantitative basis for comparing and evaluating these alternatives. This new tool was applied to a standard design for a stock preparation system in a pulp and paper mill.