First off, there's a sort of "lumpiness" to troop deployment, increasing the cost per soldier. For example, explains David Berteau, a defense expert at the Center for Strategic and International Studies in Washington, it costs more to deploy marines to quell an insurgency than it does for U.S. troops to train Afghan security forces.

Then there are the unknown unknowns, as former Defense Secretary Donald Rumsfeld might say. In November, the Government Accountability Office's head of acquisition management reminded a congressional panel that eight years into the Iraq and Afghanistan wars, the U.S. still has trouble keeping track of contractors--a problem with severe cost implications. For example, earlier this year the agency found that the U.S. Agency for International Development didn't identify personnel for a $91 million contract to refurbish a hydroelectric power plant.

The Health Blog normally ignores disease awareness days, weeks and months as pseudo-events designed to drum up media coverage. But a few nuggets pegged to this year’s World AIDS Day (today) seem noteworthy:

South Africa will provide free treatment for all HIV-positive infants under age 1 and expand treatment for others including HIV-positive pregnant women, President Jacob Zuma said. The announcement is significant not only because South Africa has the world’s largest population of HIV-positive people (5.7 million), but also because Zuma’s predecessor repeatedly denied that there was a link between HIV and AIDS. The U.S. said it would donate an additional $120 million to South Africa for anti-retroviral drugs over the next two years, on top of $572 million budgeted to help South Africa fight HIV/AIDS in 2010, the WSJ reports.

Until Tiger Woods cancelled his Tuesday news conference and participation later in the week in one of his signature golf tournaments in California, what story do you think would have received more attention on radio, television and your local newspaper Wednesday -- more details on Tiger's mysterious Thanksgiving night car crash or President Obama's widely anticipated final decision on troop increases in Afghanistan scheduled for prime time Tuesday night?

Judging from the media frenzy surrounding Woods' auto accident adventure, the odds would have been on Tiger. It's a moot point now, though, after Woods announced Monday on his Web site that he will not be playing this week at the Chevron World Challenge and won't be in action again until the PGA Tour starts up again in January.

Although a year late, the Google phone is living up to its promise. Phones based on the Web giant's Android software appear ready to challenge the iPhone, BlackBerry, and Nokia brands as a leading contender in the smartphone wars. A slew of Google phones have suddenly descended on the market, with dozens more expected to arrive late this year and early in 2010.

[Check out these technology gifts for the holidays.]