The Stock Selection Guide term, Percent Pre-tax Profit on Sales, is equivalent to Profit Margins. Before Taxes is the Net Profit plus taxes. Only taxes are added back for purposes of SSG studies. Since tax rates fluctuate, Net Before Taxes is a more stable measure. The Stock Selection Guide term, Percent Earned on Invested Capital, is equivalent to Return on Equity.
Equity is the same as Net Worth.
Return on Equity is always expressed as a percentage. Common Equity is the Book Value of Common Stock multiplied by the Number of Common Shares Outstanding. Common equity, Common Shareholder's Equity, and Common Stockholder's Equity are equivalents. It is the equity referred to in the term Return on Equity. Return on Capital is a complex notion because many variables are constantly in flux.