As it stands, the latest round of easing will see the Fed create money that will allow it to buy $40 billion of MBS each month.

Following the conclusion of its September meeting two weeks ago, the Fed said that rather than target a specific amount of purchases — the "quantitative" part of QE — it instead will keep buying until the unemployment rate hits an acceptable though unspecified level.

But Parker said that total will achieve only incremental help in the Fed's quest to spike asset prices, particularly in the stock market, and help out the housing recovery, which it hopes will generate a "wealth effect" that will lead to more hiring.

"Although QE3 is open-ended, the currently announced pace and program of purchases is much smaller than previous QE programs," he said.

Parker estimates based on the previous QE effects that the Standard & Poor's 500 will gain an average of .015 to 0.25 percentage points each week. That won't be enough to offset typical market volatility of 2.3 percent per week, nor will it be enough to spark the economy, he said.

"QE3-related gains could cumulate to 3-4 percent return by year-end, but we see headwinds — negative earnings revisions, especially for 2013, and reappearance of tail risks — that could dominate and more than offset these potential gains," he said.

Parker warns that "size matters" when it comes to QE, but said one thing the Fed got right this time was that MBS purchases, which were the focus of QE1, are more effective than purchases of Treasurys, which were the focus of QE2.

"So far, the announcement of size and composition of QE3 looks like a light version of the QE1 extension," he said.

Parker isn't the only one warning about QE effectiveness.

Capital Economics said there are too many other headwinds in the global economy for the Fed's easing efforts to be a game-changer. Moreover, the firm said pushing down mortgage rates when they already are at all-time lows also probably won't be much help the housing market.