By Jeremy Gaunt, European Investment Correspondent

LONDON (Reuters) - Investors' twin obsessions of U.S. economic decline and money market liquidity will both get an airing this week as the first quarter begins with key data and a test of central banks' effectiveness.

At the same time, a new concern is rising on equity markets about whether expectations for corporate earnings have fully taken into consideration the possibility of a severe global economic slowdown.

First, the U.S. economy, which depending on the view is either teetering on the brink of recession or already in one.

U.S. monthly jobs figures, due at the end of the week, are always carefully studied for what they say about growth. This time, however, investors will be particularly sensitive to them because of a growing concern that the U.S. consumer is being to feel pain.

"The consumer has been the last shoe to drop. Consumer spending has held up reasonably well," said Sarah Hewin, senior economist at American Express Bank.

"(But) a further deterioration in jobless data combined with the very sharp fall in consumer confidence ... suggests that the consumer is going to pull back," she said.

The Conference Board said last week that U.S. consumer confidence had hit a five-year low with fears growing over job prospects.

The issue for investors is whether this growing angst will stop consumers spending, pushing the U.S. economy deeper into trouble and spilling over into other economies, particularly those that are dependent on exports.