Rising home prices are outpacing wage hikes, and when coupled with higher mortgage rates, the financial burden of home buying has pushed affordability to a 10-year low.

I’m not a huge fan of price-to-income “affordability” measurements since the “typical homebuyer” often targeted by these formulas — the median-earning household buying a median-priced home — is a bit of a fairy tale. And these calculation don’t consider keys items such as the availability of housing — or jobs!

However, Attom Data Solution’s attempt to gauge housing affordability does give an interesting historical perspective on the monetary challenge of home buying.

Attom compares current housing conditions (pricing, incomes and rates) to what’s occurred since 2005. It’s a period that starts before last decade’s real estate bubble and continues through the long Great Recession and its recovery.

The math results in a measurement that essentially tells you how affordability is progressing. So, if the index were to be at 100 percent, conditions can be seen as average using the past 13 years as the benchmark.

For example, the typical American house hunters in the third quarter faced financial conditions where house payments would eat up 40 percent of an average American wage. (Remember, most purchases are backed by more than one income!) That’s 91.4 percent of what an average homebuyer endured in 2005 through this year. And that’s a poor score because it’s 8.6 percentage points below what you could say is a normal situation.

This represents a 10-year low and is down from 106 percent — 6 points above average — in 2017’s third quarter.

The picture painted by Attom is not pretty in the Southern California News Group’s coverage area. My trusty spreadsheet tells me that in the third quarter, the ability of a local household to comfortably purchase a home ran roughly at only 90 percent of the historic ratio of incomes to house payments.

Again, it’s housing affordability’s worst performance in a decade. And just a year earlier, local financial conditions for house hunters were running around what’s been average for Southern California.

Daren Blomquist, Attom’s key analyst, says recent affordability challenges help explain why homebuying sharply slowed in Southern California and in many parts of the nation this year. Fewer sales could eventually lead to lower prices, and hopefully, modest drops, could, in turn, raise affordability and the pace of purchasing.

“Let’s see if we can engineer a soft landing,” Blomquist says.

Here’s how Attom’s affordability yardstick breaks down in Southern California for the third quarter …

Orange County: Attom calculated the typical house payment would eat up 88 percent of what a local job paid. (Remember, dual-income buyers!) That’s buying power equal to only 90 percent of the 13-year average. Sadly, that was the region’s best. A year ago, Orange County was at 99.9 percent of long-run affordability. This drop came because the countywide median selling price of $690,000 — No. 9 nationally — is up 3.1 percent in a year while wages rose only 1.5 percent.

Riverside County: House payments run 68 percent of wages. That’s 88.9 percent of historic affordability vs. 100.5 percent a year ago. Median of $370,000 — No. 58 nationally — is up 5.5 percent in a year while wages rose 2.1 percent.

San Bernardino County: House payments run 53 percent of wages. That’s 88.7 percent of historic affordability vs. 98.8 percent a year ago. Median of $310,000 — No. 90 nationally — is up 3.3 percent in a year while wages rose 1.2 percent.

Los Angeles County: House payments run 73 percent of wages. That’s 87.2 percent of historic affordability — down from 99.4 percent a year ago. Median of $600,000 — No. 12 nationally — is up 6.2 percent in a year while wages rose 3.9 percent.

Now we all can pine for the days when affordability was in better shape. By Attom’s math, affordability last peaked in 2011’s fourth quarter in Riverside County and in 2012’s first quarter for Los Angeles, Orange and San Bernardino counties. As history also reminds you, few individuals were in a buying mood in those early days of the economic recovery.

That’s one of my major misgivings with affordability measurements. There’s no accounting for economic conditions other than home pricing and mortgage rates.

Attom’s Blomquist, noting regional real estate’s “feast or famine” nature, says a challenge to lowering the local cost of housing is that affordability seems only to come “only in famine days.”

Look at the local job market, this year’s third quarter vs. 2011 — just before affordability measurements peaked. Seven years back, unemployment in Southern California ran at 12.2 percent. In 2018, after 1.1 million jobs were created, joblessness is down to 4.5 percent. That hiring spree created many of the buyers who pushed up home prices and lowered “affordability” by traditional statistical calculations.

Yes, local housing is very pricey on a national scale. By Attom’s math, the common Orange County buyer must earn 2.8 times the national norm to buy the median-priced home. In Los Angeles County it’s 2.4 times average. Riverside County? 1.5 times. San Bernardino County? 1.2 times.