Michael is right. It was only because the Stalinist left of the thirties insisted upon foisting upon Marx their view that working class living standards would decline in absolute terms that Marx was 'disproved' by the post war boom.
In the immediate post-war Jurgen Kaczynski collated figures showing not just a relative fall in wages, but an absolute fall, too. This was actually a specific condition of the early century, but it was falsely extrapolated as a permanent condition of capitalism: an argument that collapsed in the face of the post-war boom.
The argument is laid out in Roman Rosdolsky's Making of Marx's Capital (Pluto Press).
Marx's view was complex in that he held that expressed in consumer durables or what he called 'use-values' it could be expected that working class living standards would rise over time, especially as these would fall in value due to increased labour productivity.
At the same time he argues that the share of the total social product that falls to the working class (and hence the ratio of wages to profits) ought to fall.
Recent figures suggest that wages have been almost stagnant over the period 1973-93 (Brenner, New Left Review, current), which suggest that relative wages have fallen. But Andrew Hacker provides the example of homes, to show that more people today live in apartments instead of houses than used to, and more people live in mobile homes instead of apartments than used to (Money, 1998). That suggests an actual fall in absolute wages (though many other factors would go the other way). It has often been pointed out that the way that American and British households maintained their living standards in the eighties was to double-up incomes (Kevin Phillips Politics of Rich and Poor). -- Jim heartfield