Austin is in the grips of an affordability crisis. That's not news to Austinites, really, but a large part of that crisis stems from the housing supply failing to keep up with demand.

A study out this week from Harvard's Joint Center for Housing Studies shows Austin's not alone.

In Central Texas, the study found – yes – the Austin area is increasingly unaffordable. But it found a variety of reasons for the housing shortage – namely, that Austin’s median income and its housing stock have failed to keep pace with the boom in both land prices and population.

Largely, that's the case for a lot of big cities, says study author Dan McCue. But, he says, Austin’s lag in income increase was exacerbated by its continually high housing prices, which are higher than they were during the housing boom.

“Even with the income that you’re seeing in the area, it was not enough to keep up with the house prices," he says. "So, that appears to have pushed the price-to-income ratio up higher than it even was in the mid-2000s, which is a sign of the affordability pressures."

Overall, McCue's study found there's a shortage of 260,000 homes nationwide – a trend that has continued for the last eight years.

Check out the four maps below that help explain the housing shortage in Austin and the nation. (These maps are best viewed in a desktop browser.)

Income isn't keeping pace with housing costs.

Land prices keep going up.

People are spending more of their money on housing.