A strong spring season helped home values recover, says the government.

According to the Federal Home Finance Agency’s Home Price Index, home prices rose a seasonally-adjusted 0.4 percent from April to May.

It’s the HPI’s second straight increase, and puts the monthly index at its highest point since January 2011.

As a home seller in Palo Alto , you may appreciate news such as “rising home prices”, but it’s important to remember that the Home Price Index has a several built-in flaws — the biggest of which its age.

Today, the calendar nearly reads August, yet, we’re still discussing May’s housing data. A 2-month delay does little to help buyers and sellers wanting to know the “right now” of housing.

Unfortunately, the Home Price Index data is even more aged than that.

Because the FHFA’s Home Price Index measures home prices as recorded at closing, the actual sales prices included in the index are from real estate contracts written 30-60 days prior.

In other words, when we look at the Home Price Index report for May, what we’re really seeing is a snapshot of the housing market as it existed in March. March’s housing market has little to do with the forces driving home prices today.

Today’s real estate market is driven by today’s economics.

The Home Price Index is a useful gauge for economists and law-makers; it shows long-term national trends in the housing market which can be used to allocate resources to a project, or to form new policy. For home buyers across the state of San Francisco Bay Area , though, it’s less helpful.

For today’s real estate buyers and sellers, there’s no substitute for real-time data. For that, talk to a real estate professional.

Between March and April of this year, home values rose 0.8 percent nationally, according to the Federal Housing Finance Agency’s Home Price Index. It’s the index’s first month-to-month improvement since May of last year.

Values are down 19 percent since peaking 4 years ago.

Private-sector data affirms the government’s report.

Tuesday, the S&P’s Case-Shiller Index also showed home values higher by 0.8 percent in April, on a monthly basis. Led by Washington, D.C. and San Francisco, 13 of the Case-Shiller’s 20 tracked markets showed improvement in April.

In March, just 2 markets did.

As a home seller in or near Santa Clara , it’s nice to see reports of rising home prices after multiple months of “bad news”. However, the data may not be as rosy as it appears to be. National real estate surveys including the Home Price Index and the Case-Shiller Index are flawed for everyday buyers and sellers.

The biggest flaw is “age”. Both the Home Price Index and the Case-Shiller Index report on a near 2-month delay.

This week, the calendar turns to July. Yet, we’re still discussing housing news from April. The housing market of 60 days ago was very different from the housing market of today. Mortgage rates are different, market drivers are different, and the pool of buyers is likely different, too.

We can’t discuss today’s housing market with “April” in mind. The data is irrelevant.

Another flaw is that both reports are national in scope. Real estate, by contrast, is local.

When we cite the Home Price Index or the Case-Shiller Index, for example, and say “home values rose 0.8% in April”, we’re just giving a national average. On the local level, some markets rose by more, some rose by less, and others actually fell.

People buy homes on a specific block of a specific street in a specific neighborhood. Data for homes like that can’t be captured in a national survey.

The group that gets the most value from the Home Price Index and Case-Shiller is Wall Street and policy-makers. The indices do a fair job of reporting how housing behaves as a whole, but for individuals concerned with buying and selling homes, the best place to find real-time, accurate data is from a real estate professional.

According to the Case-Shiller Index’s publisher, Standard & Poors, home values fell in March from the year prior.

The March report was among the worst Case-Shiller Index readings in 3 years. On a monthly basis, 18 of 20 tracked markets worsened. Only Seattle and Washington, D.C. showed improvement, rising 0.1% and 1.1%, respectively.

On an annual basis, price degradation was even worse.

Washington, D.C. is the only tracked market to post higher home values for March 2011 as compared to March 2010. The national index has now dropped to mid-2002 levels.

As a buyer in today’s market, though, you can’t take the Case-Shiller Index at face value. It’s methodology is far too flawed to be the “final word” in home prices.

The first big Case-Shiller Index flaw is its relatively small sample size. S&P positions the Case-Shiller Index as a national index but its data comes from just 20 cities total. And they’re not the 20 most populous cities, either. Notably missing from the Case-Shiller Index list are Houston (#4), Philadelphia (#5), San Antonio (#7) and San Jose (#10).

Minneapolis (#48) and Tampa (#55) are included, by contrast.

A second Case-Shiller flaw is how it measures a change in home price. Because the index throws out all sales except for “repeat sales” of the same home, the Case-Shiller Index fails to capture the “complete” U.S. market. It also specifically excludes condominiums and multi-family homes.

In some cities — such as Chicago — homes of these types can represent a large percentage of the market.

And, lastly, a third Case-Shiller Index flaw is that it’s on a 2-month delay. It’s June and we’re only now getting home data from March. Today’s market is similar — but not the same — to what buyers and sellers faced in March. The Case-Shiller Index is far less useful than real-time data of a city or neighborhood.

The Case-Shiller Index is more useful to economists and policy-makers than to everyday buyers and sellers in Palo Alto. For better real estate data for your particular neighborhood, ask your real estate agent for help.

A real estate agent can tell you which homes have sold in the last 7 days, and at what prices. The Case-Shiller Index cannot.

Home values dropped for the sixth straight month in March 2011, according to the Federal Home Finance Agency’s Home Price Index. The Home Price Index is a government-sponsored home value tracker.

The HPI report is the latest in a string of “falling home values” stories — a trend that’s troubling home sellers across Mountain View and nationwide.

However, although the Home Price Index says home values are falling, that doesn’t necessarily mean that they are. Like most statistics in the housing sector, the Home Price Index is plagued by poor methodologies and a lack of timeliness.

In short, the Home Price Index is flawed. In three ways.

The first big flaw in the Home Price Index is that it only measures the values of homes with mortgages backed by Fannie Mae or Freddie Mac. Homes financed via FHA, or via other means are specifically excluded from the calculation. For today’s purchase market, that leaves more than 1 in 4 homes “uncounted” — a big percentage of the market.

Second, the Home Price Index determines home values by measuring price change from sale to subsequent sale. This eliminates new homes — a major market segment.

And, lastly, the Home Price Index reports on a 60-day delay; we’re only now seeing data from March. This two-month lag renders the HPI a trailing indicator for the housing market instead of a forward-looking one. If you’re a home buyer looking for market insight, the HPI can’t give it — it’s out-dated and out of season.

Despite its shortcomings, though, we can’t ignore the Home Price Index completely. It’s among the most thorough home valuation models available, and it’s used in public policy discussions. When the HPI says prices are down, Wall Street and Capitol Hill take notice, and that trickles down to everyday life on Main Street.

Since peaking in April 2007, the Home Price Index is off 19.1 percent.

In an echo of February’s Case-Shiller Index report, the government’s own home price-tracker — the Home Price Index — showed home values slipping between January and February 2011.

The Federal Home Finance Agency data had home values down 1.6 percent nationwide in February, on average, marking the fourth straight month in which prices fell.

Furthermore, all 9 regions posted losses from the month prior:

• Mountain Region : -3.7% from January
• East South Central : -0.6% from January
• South Atlantic : -0.9% from January
• New England : -2.0% from January

Before you draw conclusions, however, note that the data at which we’re looking has several major flaws to it.

First, it’s old. We’re now in the first week of May and the FHFA’s most recent release only covers through February, a time period ending roughly 60 days ago. That’s a long delay and today’s purchase market in Palo Alto looks much different from the one of February.

Just ask a real estate agent and they’ll tell you — purchase activity is rising.

Second, the FHFA Home Price Index reports on home value changes between consecutive Fannie Mae or Freddie Mac-securitized transactions only. This might be creating an overweight of “distressed properties” in the index which, in turn, drags down valuations.

Distressed homes account for 40% of all home resales and typically sell at 20 percent discounts.

And, lastly, although the Home Price Index is a national report, real estate as a market is decidedly not national. To the contrary, it’s extremely local. As an individual, you don’t buy, sell or own homes in all 50 states. You buy them in a specific state, and a specific neighborhood ; in places like North Palo Alto.

The national data is useless to you in that respect.

We can’t discount the Home Price Index data entirely, but should remember that it paints a clearer picture of where housing has been versus where housing is going. As a home buyer or homeowner, it’s the future of home values that matters more.

Earlier this week, the private-sector Case-Shiller Index showed home prices slightly lower between November and December.  Thursday, the public-sector Home Price Index showed the same.

Publishing on a 2-month lag, the Federal Home Finance Agency said home prices fell by 1.6 percent nationally in December.  And that’s an average, of course.  Some regions performed well in December as compared to November, others didn’t.

• Values in the Middle Atlantic states improved slightly
• Values in New England were essentially unchanged
• Values in the Mountain states sagged, down 3.5%

These aren’t just footnotes. They’re an important piece toward understanding what national real estate statistics really mean. In short, “national statistics” are just a compilation of a bunch of local statistics.

For example, if we dig deeper into the FHFA Home Price Index 70-page report, we find that cities like Terre Haute, IN, Buffalo, NY, and Amarillo, TX posted year-over-year home price gains. You won’t see that in a “national” report.

Furthermore, it’s a sure bet that those same cities, you could find neighborhoods that are thriving, and others that are not.  Just because the city shows higher home values overall, it won’t necessarily be the case for every home in the city.

Every street in every neighborhood of every town in America has its own “local real estate market” and, in the end, that’s what should be most important to today’s buyers and sellers.  National data helps identify trends and shape government policy but, to the layperson, it’s somewhat irrelevant.

So, when you need to know whether your home in Palo Alto is gaining or losing value, you can’t look at the national data.  You have to look at your block — what’s selling and not selling — and start your valuations from there.