As with so many things, it all depends on whom you ask.

The National Association of Realtors says the number of first-time buyers in the U.S. market declined a full percentage point between July 2014 and June 2015.

In its annual "Profile of Home Buyers and Sellers," the Realtors' group places the blame on prospective home buyers' continued difficulty in obtaining mortgages.

The Realtors' call for looser lending standards is nothing new. It echoes the National Association of Home Builders' complaint that tight credit is keeping construction at very low levels.

Yet the American Enterprise Institute, a nonprofit think tank that favors limited government, has taken the Realtors to task for jumping to conclusions based on faulty data.

"This call for looser lending will expose first-time buyers to even higher levels of default under both normal and stressed economic conditions," said Tobias Peter, research analyst at AEI's International Center on Housing Risk.

First-time buyers are critical to the housing market because their purchases allow current homeowners to trade up to larger and more expensive homes, or to smaller houses as they age and want to downsize.

The Realtors say the percentage of first-time buyers in the market fell to 32 percent from 33 percent in those 12 months.

Peter called the Realtors' contention "more than reckless."

"To begin with, the NAR's data are wrong," he said. "The actual trend in the first-time buyer percentage is not down, but up."

In fact, Peter said, the Realtors' October report on home resales "showed that the first-time buyer share was 56 percent in October, up from 53.7 percent in October 2014.

A check of the Realtors' website confirmed that.

One month's worth of data is not sufficient to spot a trend. Quarterly data are a better indicator, but even three months' worth of numbers are not enough - a bad winter, for example, can throw things off.

Returning to Peter's argument, he said that the Realtors' group adds to "this false narrative" by concluding that "first-time buyers [are] stuck on the sidelines."

To the contrary, Peter said, his data show "first-time buyers leading the sprint this home-buying season, taking out an estimated 144,000 loans in October, up 21 percent from a year ago." Year to date, they are up 17 percent compared with the same period last year.

Loans for repeat buyers also are increasing, but at a much slower pace, he said, noting that for the year to date, these loans are up only 7 percent compared with the prior year.

Conflicting results from another survey on this topic add to the "confusion caused by the NAR," Peter said.

The monthly Realtors' Confidence Index shows that the first-time buyer share increased 2 percentage points between July 2013 and June 2014, and July 2014 and June 2015, the same period over which the Realtors also recorded a decrease of 1 percentage point, he said.

"The conflicting results from the two surveys are not a surprise, given that both have very low response rates and cover only a tiny fraction of the purchase loan market," Peter said.

For example, the buyers-and-sellers profile is based on responses from only 6,400 buyers, 0.2 percent of mortgages originated in the year, he said.

Increased first-time home-buyer activity comes with a downside - a greater reliance on looser lending, he said, and there is evidence that it already is too loose, he said.

A "return to more prudent standards is called for," Peter said.

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