In the first part of the article the author calls for more precision in the application of various indices of work effectiveness, in particular, the attempt is made to prove that the relation of total output to expenditures of direct and materialized labour is generically identical to the relation of net output to direct labour expenditures. Various aspects of the relation of the increase in labour effectiveness to personal incomes and wages to start with are elaborated in the second part of the article. The author polemizes with a common thesis of the constant need to have a higher rate of growth in the effectiveness of social labour than in real wages. The author concludes indicating at the interaction between the increase of personal income and consumption and the growth of labour effectiveness. Digitalizacja i deponowanie archiwalnych zeszytów RPEiS sfinansowane przez MNiSW w ramach realizacji umowy nr 541/P-DUN/2016