A method for determining the propagation delay of each path in an integrated circuit is provided herein. The method includes determining, in a worst-based mode, whether a propagation delay of a selected path exceeds a timing requirement; determining, in a path-based mode, whether the propagation delay of a selected path exceeds the timing requirement; and when the selected path exceeds the timing requirement in the path-based mode, lowering the cell delay of each cell in the selected path.