In a system and method, a design layout defines a transistor, a local layout effect (LLE)-inducing feature and shapes, including a non-uniform shape, that illustrate separation between the channel region and LLE-inducing feature. Layout information for the non-uniform shape, including minimum and maximum distances between the channel region and LLE-inducing feature, is extracted. Based on this layout information, a first width of a first portion of the non-uniform shape, which is associated with the maximum distance, and a second width of a second portion of the non-uniform shape, which is associated with the minimum distance, are derived and used to calculate the non-uniform shape's contribution to the value of a model parameter adjuster. The value of the model parameter adjuster is then calculated based on a sum of contributions from all shapes and used to generate a compact model for modeling a performance attribute of the transistor within the IC.