Methodological Trees and Forests

December 12, 2019
Posted by Jay Livingston

The units of analysis that researchers choose usually constrain the explanations they come up with. Measuring variables on individuals makes it harder to see the effects of larger units like neighborhoods.

For example, much research has found a correlation between female-headed households and crime. Most explanations for this correlation focus on the households, with much talk about the lack of role models or the quality of parent-child interaction. But these explanations are looking at individual trees and ignoring the forest. The better question is not “What are the effects of growing up in a single-parent home?” It’s “What are the effects of growing up in a neighborhood where half the households are headed by single mothers?”

In the early 1990s, I wrote a criminology textbook, and one of the things that differentiated it from others was that it took seriously the idea of neighborhoods and neighborhood-level variables.

That was then. But now, Christina Cross in a recent Times op-ed makes a similar argument. Research generally shows that it’s better for kids to grow up with two parents rather than one. That fits with our assumptions about “broken homes” even if we now call them “single-parent households.” But Cross’s research finds a crucial Black-White difference in the importance of this one dimension of family structure.

Looking at educational outcomes, she finds that White kids from two-parent families do much better than their single-parent counterparts. But for Black kids, the advantage of a two-parent home is not so great.
living in a single-mother family does not decrease the chances of on-time high school completion as significantly for black youths as for white youths. Conversely, living in a two-parent family does not increase the chances of finishing high school as much for black students as for their white peers.

 Why does a two-parent family have less impact among Blacks? Cross looks at two explanations. The first is that the effect of a very low-income neighborhood (“socioeconomically stressful environments”) is so great that it washes out most of the effect of the number of parents inside the home. For a kid growing up in an area with a high concentration of poverty, having a father at home might make a difference, but that difference will be relatively small, especially if the father is unemployed or working for poverty-level wages.

The other explanation is that having other relatives close by mitigates the impact of having only one parent in the home. Cross says that her data supports this idea, but the extend-family network explanation is not nearly as powerful as the neighborhood-poverty explanation.

For policy-makers, what all this means is that the traditional conservative, individual-based solutions miss the point. Exhorting people to stay married (and providing costly government programs along the same lines) aren’t going to have much impact as long as we still have racially segregated neighborhoods with high levels of unemployment and poverty.

The message for researchers is similar: if you confine your thinking or your variables to individuals, you risk ignoring more important variables.

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