The National Association of Realtors (NAR) is facing allegations of inaccurate reports of existing-home sales dating back to 2007.

Image by Monty Rakusen/cultura/Corbis

In 2010, NAR reported 4.9 million existing-home sales, down 5.7 percent from the 5.2 million existing-home sales it reported in 2009, according to the Wall Street Journal. However, California-based research firm CoreLogic paints a different picture. CoreLogic reports 3.6 million existing-home sales last year, down 12 percent from the 4.1 million existing-sales it reported in 2009.

“The last re-benchmarking to the existing-home sales series was based on 2000 Census data, so NAR is undertaking a re-benchmarking using independent sources,” says NAR’s Walter Molony tells CNBC.com. “We are consulting with various outside housing economists, government agencies, and some academic experts on the methodology to determine if there is, in fact, any drift in NAR’s existing home sales data, and, if so, by how much.”

Benchmarking refers to a point of reference in any type of inventory. For years, the NAR’s data set the standard for existing-home sale figures. According to CalculatedRiskBlog.org, in 2006 the data was readjusted, but the discrepency continued.

For an effective visual of the conflicting reports, view the graph on the Wall Street Journal’s report.