With the release of the heavily downgraded forecast from the Construction Products Association released this morning I was keen to see how the forecasters at Experian saw future workload in the industry this time around.

The answer is that they are much more pessimistic about prospects this year than they were last autumn, predicting a fall of 6.7% for 2009. This compares with a fall of 3.1% when they previously forecast.

Put another way the industry will be doing about £2.5 billion less work in today’s money this year than Experian thought just three months ago.

Interestingly the Experian forecast is far less gloomy than that released earlier today by the Construction Products Association, as Experian foresees a bounce back in 2010.

What is more, its forecasters are very bullish about prospects in the infrastructure sector. They foretell of what can best be described as boom times ahead. The numbers suggest an 8% increase this year followed by a 22% increase in 2010 and a further 8% of growth in 2011.

The net result will be the by 2011 infrastructure workload will be at the levels not seen since 1993 when John Major’s Government was pouring in cash to boost civils works in a bid to ease the pain when the UK last plunged into recession.

The big downgrades that pull the forecast down and which it can be assumed are the most vulnerable sectors are commercial and private housing RMI, along with a further downgrade for the new housing sector.

These downgrades account for about £3.5 billion less work than expected in the previous forecast. Against this the forecasters make the biggest upward revision in the forecast in the public non-housing new work sector, with about £1.4 billion more work coming through this year than they previous expected.

The reality is that forecasting construction growth at the moment is exceptionally tricky. Reasonable assumptions can be undermined so quickly at present, especially given that the Government is looking to plug some holes in the economy through bringing forward public spending.

That said, the one element of this forecast that I am uneasy with is the expectation of a swift bounce back in 2010. For my money this is a brave call.

My advice would be to read all the forecasts and make your own judgement on the assumptions they make – that is where the real value lies.