In Marx's Critique of the Gotha Program he talks about it, saying that to each according to need is communism, but in the transitional stage (socialism or workers state or whatever terminology you prefer) it is payment according to work. As I remember it, he was saying that payment according to work is not a principle of communism, but it is what will happen in real-world socialism as a part of the transition from capitalism to communism.
I don't have the Gotha Program handy here at work, but here's a good summary, found in Sam Marcy's writing about the Cultural Revolution in China: In order to understand the issue of payment according to work, one must take into account Karl Marx's criticism of the Gotha Program. The program was an attempt to describe communist society, and was written in 1875 for a Congress of the German Workers' Party. In his Critique of the Gotha Program, Marx stressed that in between capitalism and communism there would be a lengthy transition period characterized by the revolutionary dictatorship of the proletariat. In this first phase of communism, bourgeois norms would still prevail and payment, or the distribution of the social product, would be determined by the slogan "from each according to his [her] ability, to each according to his [her] work." Only in the second phase of communism could distribution be "from each according to his [her] ability, to each according to his [her] needs." source: http://www.workers.org/marcy/cd/sam91/1991html/s910620.htm -- Michael Perelman Economics Department California State University Chico, CA 95929 Tel. 530-898-5321 E-Mail [EMAIL PROTECTED]