A method of analysis of an integrated circuit design having multiple voltage islands, including: (a) determining a clock path through the voltage islands; (b) determining a data path through the voltage islands; (c) determining which voltage islands are independent voltage islands; (d) determining which voltage islands are dependent voltage islands; (e) for the data path and the clock path, performing a worst case static timing analysis based on minimum and maximum operating voltages of each independent and dependent voltage island in the data and clock paths; and (f) for the data path and the clock path, performing a best case static timing analysis based on minimum and maximum operating voltages of each independent and dependent voltage island in the data and clock paths.