Faced with weak economic data and rising fears of a double-dip recession, the Federal Open Market Committee is likely to ensure its policy is not constraining growth and to use its statement to signal greater concern about the economy. It is, however, unlikely to agree big new steps to boost growth.

Smaller measures to help the economy could initially take the form of a decision to reinvest proceeds from maturing mortgage-backed securities held by the US central bank, thereby preventing the Fed’s balance sheet from shrinking naturally.

Investors will also examine closely any changes to the pledge made by the FOMC in June to “employ its policy tools as necessary to promote economic recovery and price stability”, which could be hardened if policymakers choose to signal the potential for more aggressive move to boost the economy in the future.

But even if that happens, most economists believe that it would take several more months of poor data for the Fed to actually begin a new round of asset purchases on the scale of those carried out during the recession.

In congressional testimony last month, Ben Bernanke noted “unusual uncertainty” in the economic outlook and in a speech last week the Fed chairman warned of a “considerable way to go” before the US achieves a full recovery.

Although Fed policymakers still believe the basic trajectory of the economy remains one of moderate expansion, there may be more attention given to heightened dangers of a sharp slowdown.

“The FOMC will have to tone down its assessment of the economy in view of recent weak indicators on real growth, real consumption spending and employment,” said Brian Bethune and Nigel Gault, economists at Global Insight.

The latest poor reading came in Friday’s monthly employment report, which showed the US private sector creating only 71,000 jobs in July – not enough to keep up with population growth, let alone bring down the unemployment rate.

That followed news a week earlier that growth in US gross domestic product slowed from an annualized rate of 3.7 percent in the first quarter to 2.4 percent in the second quarter.

“Given how low inflation already is, and given the potential for the recovery to falter, we expect Fed officials will highlight downside risks and signal a bias to ease in the FOMC statement,” said Jim O’Sullivan, chief economist at MF Global.

There is little, if any, doubt that the FOMC will maintain interest rates at their current low target range of 0-0.25 percent.