Tracking Worldwide HIV Infections

By Matt Stiles | | Topics: Demographics

This week Washington is hosting the International AIDS Conference, and one of my colleagues crafted this interactive to show how HIV infection rates differ by country and region.

According to STDAware, the red lines below show the percentage of the adult population infected with the disease in Middle, Eastern and Southern Africa, regions in which about eight percent of the population is infected. In some countries, though, the rate is higher than 20 percent:

Monitoring D.C.’s Growth With Landsat

By Matt Stiles | | Topics: Demographics

Yesterday was the 40th anniversary of the Landsat system, a group of satellites that offer scientists a continuous view of the earth.

“The data from the satellites provide a permanent, objective record of land conditions and are routinely used to measure and monitor changes brought on by natural or anthropological events and actions,” according to the U.S. Geological Survey, which operates the system in partnership with NASA.

Here’s an example. Four decades ago, the system took this color infrared image of the Washington, D.C., area. “The red tones represent forests and large grassy areas. The light tones indicate cleared fields and the highly reflective impervious areas of urban development,” according to USGS:

Landsat also captured this image earlier in 2012. “A comparison of the two images illustrates the significant growth in the greater D.C. area,” the agency said:

More about the Landsat system here:

Charting Unmarried Households And The Effect On Kids’ Future Income

By Matt Stiles | | Topics: Demographics, Economy & Finance

The New York Times has a fascinating story today about links between marriage and children and the growing class divide in America. The story focuses on two families — one led by a married couple, Chris and Kevin Faulkner; the other by a struggling single mom, Jessica Schairer:

The economic storms of recent years have raised concerns about growing inequality and questions about a core national faith, that even Americans of humble backgrounds have a good chance of getting ahead. Most of the discussion has focused on labor market forces like falling blue-collar wages and lavish Wall Street pay.

But striking changes in family structure have also broadened income gaps and posed new barriers to upward mobility. College-educated Americans like the Faulkners are increasingly likely to marry one another, compounding their growing advantages in pay. Less-educated women like Ms. Schairer, who left college without finishing her degree, are growing less likely to marry at all, raising children on pinched paychecks that come in ones, not twos.

The story is accompanied by two charts illustrating the trend. The first shows how the rate of women having children outside of marriage has increased among all racial groups:

This chart shows that children who don’t live with both parents are less likely to move up to higher income groups as adults:

How Common Is Your Birthday? Pt. 2.

By Matt Stiles | | Topics: Demographics

Last weekend’s birthday heatmap post has been hugely popular by The Daily Viz standards, drawing in more than 100,000 readers and tons of social media attention. While I’m excited about the traffic, I’m also worried that the graphic may have misled some readers.

Some people read the map assuming that darker shades represented higher numbers of actual births, even though I tried to explain in the post that the colors were shaded by birthday rank, from 1 to 366, in popularity. Or I thought I did. Because of that, Sept. 16 — the most popular birthday — seems wildly more common than January 1, among the least popular. Both may be relatively close in the raw number of births, even though their ranks are far apart.

Unfortunately, I haven’t yet been able to acquire a list of all dates and total births for each. But last night I compiled a decade’s worth of nationwide birth data by month. Those data show that August, in fact, saw the most births during the 10-year period. Each month is over 3.1 million births, however:

August, of course, has an extra day for potential births, so I created an average births by month field. Viewed that way, September did have more births relative to its size. But notice there isn’t much difference between months in the distribution of the births. Alas, all our birthdays are probably pretty normal:

I should note that this blog is a place for me to experiment with visualization techniques in my own time, and I will occasionally make bad design choices or produce work that is less useful to some. This is one of those times, I suppose. Thanks to Dan DeFelippiWaldo Jaquith and several others who prompted this post. Download the data if you want to create your own visualizations.

Data source: Centers for Disease Control, National Vital Statistics Reports

Is Mom More Important Than Dad?

By Matt Stiles | | Topics: Demographics

Perhaps mom is more important online, at least according to Google’s Insights for Search. This chart shows search volume in the United States over the years for the words “mother” and “father,” suggesting that more people online want information about mothers:

Here’s a similar chart for “mother’s day” and “father’s day”. Same trend, though dad did OK last year:

How Common Is Your Birthday?

By Matt Stiles | | Topics: Demographics

UPDATE: I’ve written a clarification about this post here. Please read it

A friend posted an interesting data table on my Facebook wall yesterday, which was my birthday. The data listed each day of the year with a ranking for how many babies were born in the United States on each date from 1973 to 1999. Some interesting trends are evident in the data. Apparently, people like to make babies around the winter holiday season because a large proportion of babies are born in September (ours is due Sept. 24, btw).

Sept. 16 was most common. Feb. 29* was least common. This heatmap is an effort to visualize the trends, with darker shades representing more births:

Data source:, Amitabh Chandra, Harvard University

Follow Matt @Stiles on Twitter.

* A previous version of this post incorrectly listed Jan. 1 as the least common birth day. 

Comparing President Obama’s Job Approval Rates Among Different American Groups

By Matt Stiles | | Topics: Demographics, Policy & Politics

President Obama’s approval rating has crept just above 50 percent, his best position in a year, the latest Gallup survey figures show. The Washington Examiner adds some historical context:

Obama’s numbers peaked at 53 percent in the last week of May [2011], but then dipped below 50 percent in June [2011]. His approval ratings sank to a low of 38 percent in October 2011, before returning to 50 percent in mid-April 2011.

Click on the image to interact with the charts.

Using Gallup’s weekly trends data — which can be sliced into groups based on religion, gender and party identification, among other categories — I created numerous interactive charts to show the trends since his presidency began in January 2009.

The charts reveal some interesting, though perhaps not unexpected, trends. First, of course, there’s a clear partisan divide: 83 percent of Democrats approve of the president’s performance while just 13 percent of Republicans approve, according to the most recent weekly trends data provided by Gallup (through April 29).

But other differences are evident.  Only 40 percent of people who told Gallup that they attend church weekly approve. Compare that with 54 percent approval among people who rarely go to church. Older and wealthier people also approve at lower rates.

I’ve broken the numbers out into 21 different area charts. Explore them here.

A warning: The page is a bit sluggish in Internet Explorer. I haven’t had time to fix that. So, click here to get a proper browser.

UPDATE: I added fresh data on May 27, so the graphics are current. Check them out.

‘Sprawl On The Skids’

By Matt Stiles | | Topics: Demographics

Nice before/after map and story from USA Today about how suburban growth has slowed: 

Five years ago, millions of Americans were streaming to new homes on the fringes of metropolitan areas. Then housing prices collapsed and the Great Recession slowed growth to levels not seen since the Great Depression in the 1930s. Growth remained slow last year, and largely confined to counties at the center of metropolitan areas. Maps show population gain or loss in 2006 and 2011, based on new Census Bureau estimates.

Anyone have thoughts about the colors? Though muted, they could remind readers of politics maps. 

Mapping Asian Population Density With Census Data

By Matt Stiles | | Topics: Demographics

Asians were the fastest-growing racial group in the United States from 2000-2010, growing by nearly 30 percent in most states, according to a new report by the U.S. Census Bureau released today: 

The population that identified as Asian, either alone or in combination with one or more other races, grew by 45.6 percent from 2000 to 2010, while those who identified as Asian alone grew by 43.3 percent. Both populations grew at a faster rate than the total U.S. population, which increased by 9.7 percent from 2000 to 2010.

This map, made with ArcGIS, visualizes that population with a dot density map. Each dot represents 3,000 residents per county: 

Census Bureau Releases 1940 Data. America Has Changed.

By Matt Stiles | | Topics: Demographics

After 72 years, the U.S. Census Bureau today released data from its decennial count in 1940. The release includes a fascinating graphic about how Americans have changed over time. Here’s just one section, comparing our workforce: 

There’s much more in the graphic: housing, demographics, etc. Check it out