The only type of infographic I believe in is a Venn diagram, as it describes relations instead of reporting statistics. Perhaps my favorite Venn diagram is two intersecting circles, one labeled "Bat," the other labeled "Man," and their intersection labeled "Batman.” Perfectly accurate.
So what shall we think about this Williams Institute infographic reported in The Atlantic? It shows the percentage of same-sex couples raising children to be significantly higher in cities or states with same-sex-marriage bans. For example, in Salt Lake City, Utah, home of the Church of Jesus Christ of Latter Day Saints, also known as the Mormon Church, 26% of same sex couples have children, whereas in Washington, D.C. that number is 8.7%.
What we have here is an instance of statistical dilution. If your sample size is very small, it takes fewer people to equal a certain percentage. Twenty-five percent of 100 is 25 people. Twenty-five percent of 100,000 is 2,500 people. While both measure 25%, the numbers are in no way equivalent.
So a low density of same-sex couples partially explains the Williams Institute’s numbers. The Atlantic further tries to explain this by stating that people in certain areas of the country are more likely to want to have children. Essentially, the more rural an area, the more likely "family" will be emphasized in a person’s life. Therefore, they will want to stay where they are despite outside pulls, and start families of their own. The Atlantic does not quote statistics on this, and that’s probably for the best. Plenty of people in large cities start families and stay put. Furthermore, the study breaks down their statistics into two groups of Metropolitan Statistical Areas, defined as a city center with outlying suburban areas comprising one or more counties. These are then sub-defined as population of one million or more, and one million or less.
While this may not seem sufficient to determine an exact account of their sample size, we can be relatively certain that all the areas surveyed are at least nominally urban, and that they contain sufficient amounts of same-sex couples wanting to settle down and start families, no matter how urban the area.
As an anthropologist, I understand the desire to categorize segments of human behavior. It’s fascinating to find out which portions of the population are having children and why, and it’s important to continue to give all men and women access to social services and government protections, like insurance, adoption, power of attorney, and the over 1,500 rights guaranteed by marriage and domestic partnerships. This type of statistical analysis can be used to benefit people, but only if you keep firmly in mind that statistics can be used to prove almost anything, depending on who is doing the interpretation.
Also, this particular survey does not do that great a job getting at the "why," or more importantly, the "how." While we should definitely keep in mind the dilution factor of large vs. small populations, it is even more important to focus on what is truly important — that families anywhere are happy and healthy and supportive.