Newly released data from the US Census Bureau has just revealed that the average household size is increasing for the first time in over 160 years. Put differently, the formation of new households has started to trail overall population growth. And that is causing the average number of people per household to increase.

In 1790, there were about 5.79 people per household in the United States. That number has been in decline pretty much since then, though there was a slight increase in the decade that began in 1850. Last year (2018), the number grew to 2.63 people per household (2.71 for owner occupied households and 2.48 for renter occupied households).

Here are two charts from Chris Fry's recent piece at the Pew Research Center:

So what is causing this?

Well, we know that US fertility rates aren't on the rise. In fact, they're generally viewed as hitting record lows. I say "generally" because there are a number of different ways to measure fertility. There's the general fertility rate, completed fertility, the total fertility rate, and others. But we are seeing some alignment here: fertility rates are down.

One probable explanation is the fact that more Americans are living multi-generationally. According to the Pew Research Center, 1 out of every 5 Americans lived in such a household as of 2016. Part of this may be a result of immigration. Asian and hispanic populations are more likely to live in a multi-generational household compared to white people.

Another demographic trend is the increase in people living in shared quarters, whether that might be with a roommate or someone else. This is interesting because it suggests that there's an affordability constraint. Are people being forced to "double up?" The current co-living trend is at least partially because of this.

These are all noteworthy trends because household formation is viewed as "the underlying driver of long-term demand for new housing." I am assuming that more people per household also means less square footage per person.

Graphs: Pew Research Center

Newly released data from the US Census Bureau has just revealed that the average household size is increasing for the first time in over 160 years. Put differently, the formation of new households has started to trail overall population growth. And that is causing the average number of people per household to increase.

In 1790, there were about 5.79 people per household in the United States. That number has been in decline pretty much since then, though there was a slight increase in the decade that began in 1850. Last year (2018), the number grew to 2.63 people per household (2.71 for owner occupied households and 2.48 for renter occupied households).

Here are two charts from Chris Fry's recent piece at the Pew Research Center:

So what is causing this?

Well, we know that US fertility rates aren't on the rise. In fact, they're generally viewed as hitting record lows. I say "generally" because there are a number of different ways to measure fertility. There's the general fertility rate, completed fertility, the total fertility rate, and others. But we are seeing some alignment here: fertility rates are down.

One probable explanation is the fact that more Americans are living multi-generationally. According to the Pew Research Center, 1 out of every 5 Americans lived in such a household as of 2016. Part of this may be a result of immigration. Asian and hispanic populations are more likely to live in a multi-generational household compared to white people.

Another demographic trend is the increase in people living in shared quarters, whether that might be with a roommate or someone else. This is interesting because it suggests that there's an affordability constraint. Are people being forced to "double up?" The current co-living trend is at least partially because of this.

These are all noteworthy trends because household formation is viewed as "the underlying driver of long-term demand for new housing." I am assuming that more people per household also means less square footage per person.

Graphs: Pew Research Center