There are different measures of the rate of profit. Brenner uses manufacturing. Doug uses measures for the entire economy. Both measures rely on estimates of the value of capital goods, which nobody really knows because one can only use rules of thumb for depreciation & ignore the effect of technical change devaluing the capital stock.
-- Michael Perelman Economics Department California State University Chico, CA 95929
530 898 5321 fax 530 898 5901 http://michaelperelman.wordpress.com