As it turned out, all that mattered this week was the first trading day of the year.

Stocks slipped slightly on Friday, and they have now fallen back to the levels the market attained after a breakout rally on Monday.

Investors did get the market off the mat, however — the Dow Jones Industrial Average fell 23 points to finish at 11,675, but had fallen to a half-point below 11,600 earlier in the session.

 The Nasdaq and S&P 500 indices also posted modest losses.

We financial-media types were unanimous in tying the trading session’s final results — and overall loss — to the morning’s employment data, but, really, do we know what would’ve happened had there been no jobs report today?

The data was out an hour before the opening bell, and stocks subsequently opened flat, crossed into positive territory, sold off heavily, then rallied for a slim loss. Gleaning the cause-and-effect in stocks is often a fool’s errand, especially across the trading duration of one session.

 More than likely, the jobs report simply added another point of contention around which bulls and bears could battle — as they have been doing all week. The ultimate issue is whether the rally from mid-September, which was super-sized again through December, is running out of steam, especially in the face of hard economic data that doesn’t fit into an optimist’s plans?

That’s not to say the jobs report carried no weight on Friday — bonds, for example, caught a bid, driving yields down to 3.3%, their lowest closing point so far in 2011.

Financial stocks also had a difficult day. The Financial Select Sector SPDR (NYSE:XLF) exchange-traded fund slipped 0.9% and is now off 1.5% in the past two sessions, creating a serious drag on any attempts to drive the overall market higher.

The initial headline on December’s unemployment rate — that it fell to 9.4% from 9.8% — had a nice shine to it, until one read further and realized that only 103,000 jobs were created (well below expectations of 150,000) and that 260,000 people dropped from the labor force.

The more significant data point of employment-to-population ratio gained one whole percentage point, but still remains near the lows of the downturn.

And does it really seem like a good thing that a majority of the job growth that is happening is the kind that’s putting people 55 and over to work?

That’s another question that may eventually put the stock rally to the test.