This tutorial will present the NGOMSL methodology for constructing and using GOMS models for use in analytical user interface design evaluation. The first half-day will present the basic concepts of GOMS models, the NGOMSL notation, a procedure of conducting the analysis, and obtaining and using usability predictions. The second half-day will be a lab session in which with the help of the instructor, participants will construct and make use of a GOMS model for a suitable subset of a user interface design.