The housing market’s bottom is 9 months behind us. Home values continue to climb nationwide.

According to the Federal Home Finance Agency’s Home Price Index, home values rose 0.8% in May on a monthly, seasonally-adjusted basis. May’s reading marks the sixth time in seven months that home values rose.

Values are now higher by 4 percent since the market’s October 2011 bottom.

As a home buyer or seller, though, it’s important to understand what the Home Price Index measures. Or, more specifically, what the Home Price Index doesn’t measure.

Although widely-cited, the HPI remains widely-flawed, too. It should not be your sole source for real estate data.

As one example of how the Home Price Index is flawed, consider that the HPI only tracks the values of homes with an associated Fannie Mae- or Freddie Mac-backed mortgages. Homes with mortgages insured by the FHA are excluded, as are homes paid for with cash.

5 years ago, this wasn’t a big deal; the FHA insured just 4 percent of the housing market and cash sales were relatively small. Today, though, the FHA is estimated to insure more than 30% of new purchases and cash sales topped 17 percent in May 2012.

That’s a sizable subset of the U.S. housing market.

A second flaw in the Home Price Index is that it tracks home resales only and ignores new home sales. New home sales represent roughly 10% of the today’s housing market, so that’s a second sizable subset excluded from the HPI.

And, lastly, we can’t forget that the Home Price Index is on a 60-day publishing delay.

It’s nearly August, yet we’re only now receiving home valuation data from May. A lot can change in the housing market in 60 days, and it often does. The HPI is not reporting on today’s market conditions, in other words — it’s reporting on conditions as they existed two months ago. Information like that is of little use to today’s buyers and sellers.

For local, up-to-the-minute housing market data, skip the national data. Talk with a local real estate agent instead.

Since peaking in April 2007, the FHFA’s Home Price Index is off 16.0 percent.

The Federal Home Finance Agency’s Home Price Index shows home values up 0.8% in April on a monthly, seasonally-adjusted basis.

April marks the third consecutive month during which home values increased and the index is now up 3 percent from last year at this time.

As a home buyer , it’s easy to look at the Home Price Index and believe that its recent, sustained climb is proof of a broader housing market recovery. Ultimately, that may prove true. However, we cannot base our buy-or-sell decisions on the HPI because, like the private-sector Case-Shiller Index, the Home Price Index is flawed.

There are three main flaws in the FHFA’s Home Price Index. They cannot be ignored.

First, the FHFA Home Price Index’s sample set is limited to homes with mortgages backed by Fannie Mae or Freddie Mac. By definition, therefore, the index excludes homes with mortgages insured by the FHA.

5 years ago, this wasn’t such an issue because the FHA insured just 4 percent of mortgage. Today, however, the FHA’s market share is estimated to exceed 30 percent.  This means this the HPI excludes more than 30% of U.S. homes from its calculations right from the start.

The index also excludes homes backed by the VA; jumbo mortgages not securitized through the government; and, portfolio loans held by individual banks.

Second, the FHFA Home Price Index is based on the change in price of a home on consecutive home sales. Therefore, it’s sample set cannot include sales of new home sales, nor can it account for purchases made with cash because cash purchases require no mortgage.

Cash purchases were 29% of the home resale market in April.

Third, the Home Price Index is on a 60-day delay.

The report that home values are up 0.8% accounts for homes that closed two months ago, and with contracts from 30-75 days prior to that. In other words, the Home Price Index is measuring housing market activity from as far back as January. 

Reports such as the Home Price Index are helpful in spotting long-term trends in housing but data from January is of little help to today’s new jersey home buyers and sellers. It’s real-time data that matters most and the best place to get real-time housing market data isn’t from a national home valuation report — it’s from a local real estate agent.