How could San Francisco’s rental market be “affordable” in a national study that scores Los Angeles rather poorly?

Data crunchers at apartment tracker RentCafe tried to measure the cost of renting a slightly different way — where are rental units the most affordable to the common paycheck.

RentCafe analysts looked at Census Bureau housing data for the nation’s 50 most-populous cities to see how rents and incomes stacked up. These researchers defined “affordable” as how much of the rental supply would cost a tenant less than 30 percent of their salary — then compared results for 2017 to 2011, early in the economic recovery, to see where affordability improvements were made.

“A look at the cross-section of where the job market and the housing market intertwine reveals what the rental market has to offer and for how much, and most importantly, how much of it can renters afford,” the report states.

Nationally, 49 percent of U.S. big-city rental units were “affordable” by this math and that was an 11 percentage-point improvement between 2011 and 2017. It’s worth noting the financial situation of the typical renter looks better today than post-recession. Overall family finances have improved and more well-to-do folks are opting to rent, both due to fear of ownership and its high cost.

California cities in the study got mixed results. Solutions for California’s high housing costs are a hot topic with Proposition 10, a rental-control expansion issue, on the statewide ballot Tuesday, Nov. 6.

In this renter study, Raleigh, N.C., fared best with 71 percent of its rental units seen as affordable — No. 1 of the 50 big cities studied — and that was up 28 percentage points in six years, also the top performance.

But the runner-up was a surprise. San Francisco showed 68 percent of its rental units are affordable. The city ranked No. 2 out of the 50, up 25 percentage points in 2011-2017, the second biggest improvement performance.

Here’s RentCafe’s take: “Big paychecks and rent control have led to a unique situation in San Francisco. The median renter household income clocked in at $92,123 in 2017, almost 2.4 times the national level. It’s worth noting, though, that this high accessibility rate is also influenced by the 60 percent share of rent-controlled units.”

The same math wasn’t as generous to the rental market of Los Angeles, where just 23 percent of rentals were affordable, fifth-worst among the 50. And L.A. has rent control, too. But the Los Angeles market had a meager rebound by this math — affordability was up 2 percentage points in six years, the No. 38 out of 50.

My own study of census rent data, on a county level, also revealed oteworthy “affordability” in San Francisco County. Just 37.1 percent of residents paid more than 30 percent of their income to the landlord, best among 141 most-populous counties studied. And those rentals had typical had 2.18 residents, 16th lowest crowding among the 141. Los Angeles County had 57.8 percent of its rental households financially “burdened,” eight-worst nationally.

In the Bay Area, you could argue San Francisco’s rent control moved the challenges outward. Huge, tech-related paychecks — combined with limited supply — have made renting a challenge for folks lacking sought-after skills.

Yes, Oakland had the ninth-biggest affordability improvement — 42 percent of its rental units were affordable (No. 31 of the 50), that’s up 15 percentage points in six years. San Jose has just 45 percent “affordable” units — No. 26 of the 50 cities tracked — up only 5 percentage points in six years. And at No. 42 was Sacramento with 32 percent affordability — No. 42 of the 50 — down 1 percentage points in 2011-17.

Other Southern California results were mixed. Eighth-best improvement was in Long Beach with 48 percent of its rental units affordable — No. 18 of the 50 — up 16 percentage points. No. 16. was San Diego at 42 percent affordable — No. 31 of the 50 — up 11 percentage points.