ROCE uses pre-tax operating-income over capital employed, which makes it insensitive to tax domicile but not comparable with an after-tax wacc without adjustment. It is the standard measure in mining, energy and industrials.
Because capital employed is derived straight from the balance-sheet, ROCE is quick to compute and hard to argue with, which is its main advantage over the many competing return-on-invested-capital definitions.
Example: Northwind Tools has $1,480M of assets less $310M of current liabilities, so capital employed is $1,170M. On $120M of EBIT that is a 10.3% ROCE.
Related: return-on-invested-capital, operating-income, invested-capital, balance-sheet, economic-profit