New-home sales took an unexpected dive in January, dropping 11.2% on a monthly basis, according to data released Wednesday by the U.S. Census Bureau.

That translates into a seasonally adjusted level of 309,000 new home sales, which stands 6.1% below the same month one year ago.

Analysts and economists presented conflicting reasons for the numbers.

Patrick Newport, U.S. economist for IHS Global Insight, noted that single-family permits—a key leading indicator of housing and economic activity--have been increasing for the past three months. “It now appears that builders were planning to ramp up production, anticipating a surge in demand from the second home buyer's tax credit,” he said. “It also appears that this surge is not materializing.”

Equity analyst Michael Rehaut, who follows the public builders for JP Morgan, had a different take on the January new home sales numbers. “We … note this drop in activity is inconsistent with several builders' commentary over the last few weeks that January showed solid order trends. As a result, we view this data point as more of an anomaly rather than any material cause for concern,” he wrote in a research note.

Still, a key measure of consumer confidence tumbled in February, so builders and others might be waiting nervously for the February new-home sales numbers to be released next month.

January's inventories rose slightly, to a seasonally adjusted number of 234,000 homes. New homes continue to spend a long time on the market before selling—a median of 14.2 months in January. According to Newport, that represents an “all-time high” since the government began collecting that data in 1963. “During normal times, homes sell within five months,” he said.

Prices also softened, falling 5.6% on a monthly basis to a median of $203,500.

Alison Rice is senior editor, online, at BUILDER magazine.