A year of stimulus makes a big difference to a battered economy, but a quarter-point makes more of a difference to investors.

On Feb. 17, 2009, President Barack Obama signed a $787 billion stimulus package. It staved off economic ruin, though fierce debate and political upheaval continue to shape opinions over how much it helped spur recovery.

One clear sign that it has done at least part of its job came at the end of last week.

When the Federal Reserve on Thursday announced a surprise 0.25% boost to the rate it charges banks for emergency loans, the timing threw many investors, but economists and strategists with a longer view called it a natural, encouraging move. Yet, the market reaction offered another illustration of how the gears of the market and the gears of the economy can grind against one another in a balky recovery.

"The hike in the discount rate from 0.5% to 0.75% was only a surprise because of the timing, but the Fed had been warning for some time that this was going to be part of the process of taking the emergency stimulus out of the financial system," wrote David Rosenberg, chief economist and strategist at Gluskin Sheff, in a Friday commentary.

Bruce Kasman, JPMorgan's chief economist, offered a similar view immediately after the Thursday announcement, but said that this minor piece of the interest rate puzzle won't push the Fed to move faster as it backs off its quantitative easing policy of very low interest rates.

"The timing of the announcement was designed to reinforce this separation of the discount rate spread normalization and monetary policy, he said. This move does not alter our view that the Fed's first policy rate hike will come in the first half of 2011."

A survey released Monday by the National Association of Business Economists supports an essentially positive view of the U.S. recovery, though it also underscored its choppy, hard-to-predict nature.

We see a healthy expansion under way, although it will take time to reduce economic slack and repair damaged balance sheets, said NABE President Lynn Reaser, chief economist at Point Loma Nazarene University.

The group "expects the economic recovery to remain firmly on track," with real GDP growth of 3.1% projected over the four quarters of 2010, nearly identical to last November s prediction of 3.2%.

However, some difference of opinion remains. "When asked to qualitatively characterize the economic recovery, panelists ascribed to no dominant view but suggested a variety of characterizations," the report said. "The most popular view, by a small margin, describes the outlook as a traditional economic expansion in its early phase, with above-trend growth and gradually firming inflationary pressures."

Although equity markets can reasonably be expected to remain volatile as the recovery engages a year after the stimulus was enacted, Ed Yardeni, a reliably bullish voice, says the possible double-dip may turn out to have been barely a divot.

"Is the correction over already?" Yardeni, the founder and chief economist of Yardeni Research, wrote Wednesday. "If so, then it s probably because corporate earnings continue to surprise to the upside."

On a closing basis, the S&P 500 peaked at 1150 on Jan. 19, Yardeni noted. The index then dropped 8.1% to 1057 on Feb. 8, when it came close to, but remained 3% above, its 200-day moving average, which continues to rise. "Unless the market takes another dive soon, the recent downdraft may not even rate as an official 10%+ correction."

But policy analysts Tom Gallagher, Andy Laperriere and Melissa Loesberg of ISI Group warned that, like the markets, the government will move unevenly as it lets the economy re-engage while it softens its intervention.

The stimulus exit is "likely to be in fits and starts," they warned recently. Brace yourself for more feints and fizzles on the path to recovery.