Illustrating Geographical Distributions and Describing Populations Using Data from the U.S. Census Bureau
In a previous post I give an example and step-by-step instructions for the geocoding process (converting street address locations to lat/long coordinates). In another previous post I give an example and step-by-step instructions on how to use QGIS to illustrate the spatial distribution of geocoded addresses as a point and choropleth map as well as how to perform a ‘spatial join’ that will identify each location with an associated geography (using a geo identifier for Census tract, zip code, legislative district, etc – whatever your geographic level of interest).
In the current post, using ArcMap rather than QGIS (though it is the same conceptual process), I provide an example and step-by-step instructions for taking this one step farther and joining actual U.S. geography-based Census demographic data to the address locations file without ever leaving the ArcMap platform.
Step 1, Download the Tract Shape and Data File: The U.S. Census Bureau provides downloads that contain both the tract level shape file (the underlying map) along with selected demographic and economic data. These data are derived from the American Community Survey (ACS) and are presented as five-year average estimates since the ACS is carried out through sampling and it requires a five year pooling of the data to arrive at reasonably accurate estimates. In this case I have elected to download the national file that reflects the most recent 2010-14 tract level data estimates. Click here for a direct link to the U.S. Census Geodatabases page.
Part Two: From Geographic Location to Neighborhood Profile
In Part One of this two part blog post I explained how to start with a list of street addresses and, using Google’s Fusion Tables function, map those locations onto an interactive Google Map. This tool alone can be very useful and powerful in the context of institutional research and administration. However, where spatial analysis becomes significantly more powerful is when you use these known locations to find out more information about the specific communities and neighborhoods of students and alumni. Through the use of spatial analysis software, these “point” locations can be tied directly to zip codes, census tracts, block groups, Congressional districts, etc. From there, geographic data from the Census Bureau’s American Community Survey or other sources can be used to understand a great deal about where the community and neighborhood profile of students and alumni. It’s only a proxy for the individual and we always need to be aware of the Ecological fallacy, but you can gain immense and detailed understanding of a group just by learning about their spatial location.
The following is a guide for taking individual records (including street addresses), overlaying geographic boundaries (such as tracts, zip codes, etc.), joining (or combining) the individual records with their respective geographic descriptors (e.g. Student A lives in zip code 12345), and finally, joining/combining geography-based data from the US Census’ American Community Survey to those individual records (e.g. Student A lives in zip code 12345, which has a population of 3,500, a median household income of 65,000 dollars per year, and so on).
Part One: Making Use of Mapping in Institutional Research
A good visual can be a helpful tool considering that the job of an Institutional Researcher is to keep the attention of people who have many important things to do with their time and little time to spend wading through a lot of text and long explanations. Enter mapping and spatial analysis. Maps generally make for familiar, easy to read, and aesthetically pleasing images that grab viewers’ attention and, when carefully constructed, do a very good job of communicating information. They are nice to look at, but they can also tell us relevant and important about our institution. I elaborate on a specific technique in this post (Part One) and delve more deeply into the topic in a follow-up post (Part Two). In this post I illustrate a simple but effective technique for mapping point locations. In the following post (Part Two), I discuss some of the potential deeper applications for mapping and spatial analysis in Institutional Research.
Anecdotes often get a bad rap – sometimes deservedly. We have all seen examples of narratives plucked from the public smorgasbord and used to prop up a pre-conceived ideology. Given the prevalence of this often irresponsible and manipulative use of narrative [discussed further in the Huffington Post’s “The Allure of an Anecdote”] it is easy to lose faith in the power of stories. This periodically leads to a surge in demand for hard data and evidence regarding everything from healthcare to higher education. But data and statistics take their fair share of heat as well. For one thing, it turns out that data analysis is subjective too. Data can be manipulated, massaged, and infused with bias. And the strictly ‘objective’ quantitative analysis tends to come across as cold, devoid of feeling, and uninteresting. We know enough to know that numbers never tell the whole story. Standardized testing alone is a grossly inadequate assessment of educational enrichment and when organizations uncompromisingly focus on ‘the bottom line,’ it makes most of us uncomfortable at best.
This methodological tension is an exemplar of how the solution is rarely to be found in the extremes. Unfortunately, these two approaches to knowing the world have such strong advocates and detractors that we are often drawn toward diametrically opposed camps along a false continuum. Compounding the problem is that shoddy and irresponsible research at both ends of the spectrum is regularly circulated in mainstream media outlets.
This divorce is particularly problematic given that quality science, good journalism, and effective research tend to integrate the two. So-called “hard data and evidence” need narrative and story to provide validity, context and vitality. On the other hand, anecdotes and narratives need “hard data and evidence” to provide reliability, and to help separate the substantive from the whimsical. In responsible and effective research and analysis, the methodological dichotomy is brought into synergy, working together as structure and foundation, flesh and bone. The Philadelphia Inquirer printed a series on poverty in 2010 that serves as a good example from the field of journalism [“A Portrait of Hunger”]. Done effectively, data and narrative are inextricably melded into a seamless new creation.
In my short time thus far in Institutional Research at Swarthmore, I have been impressed by many things, one of which is the simultaneous respect for research and evidence-based decision making alongside respect for stories, nuance, and humanity. When the values and mission of a college call for an environment that respects both, it facilitates the practice of effective and balanced institutional research.