Lancaster County

My first post is focused on comparing Lancaster County, Pennsylvania and its largest city, Lancaster, to a handful of counties and their respective largest cities.  The comparable counties were selected for one of two reasons. The first was if they are located in the same region as Lancaster. This is the case for York, Cumberland, Dauphin, and Lebanon Counties.  The second was if the counties have certain attributes that I think make them an interesting comparison to Lancaster.  The most common characteristic for the second group is their proximity to major urban areas. Cumberland County, ME; Pierce County, WA; Sacramento County, CA; Milwaukee County, WI; Lehigh County, PA; and Lackawanna County, PA are all located within a one to two hour drive of major metropolitan areas. This makes them an interesting comparison to Lancaster--which is about a 1.5 hour drive from Philadelphia.  Travis County, TX; Davidson County, TN; and Buncombe County; NC were all selected because they are home to growing and vibrant cities (Austin, Nashville, and Asheville) and therefore serve as reasonable "model" counties that can be useful comparisons.

The following two tables display selected statistics for the counties (in the first table) and the cities (in the second table). Take quick look at the two tables and see if you can identify any trends.



By glancing back and forth at the two tables, you can start to see that there are some noticeable differences between the counties and their largest cities.  You might start to notice that the high school graduation rate appears to be higher in the counties than the cities, or you might notice that median household income looks higher in the counties than the cities.  But to really start gaining a thorough understanding it can be very helpful to visualize the data.  The following series of charts are aimed to more easily identify patterns between Lancaster County and Lancaster City and the other counties and cities in the tables above.

The first bar chart visualization compares high school graduation rates.  It is organized by grouping all county/city combos together so their high school graduation rates can be compared side by side. For example, York, PA is found at the top of the chart. By hovering over the bar for county a tooltip will appear that displays details of that data point.  We see that York County has a high school graduation rate of 88.4 %.  If we move the cursor over the city bar, we see that York City has a high school graduation rate of 76.5 %, which is an 11.9 percentage point drop from the county. The difference between the county and the city for each group is displayed at the end of the city bar.  The chart is sorted from the county/city combo with the largest negative difference at the top to the combo with the smallest difference at the bottom.  Of the sample counties in this analysis,  York, PA has the largest negative county/city delta (11.9 percentage points) while Buncombe, NC has the smallest. In fact, Buncombe is the only group in which the city (Asheville) has a higher graduation rate than the county.

Take a minute to explore the data on your own. Do any patterns start to emerge?

You may have noticed that counties in Pennsylvania appear to have larger negative high school graduation rate deltas between county and city than comparable combos in other states. Indeed, of the 14 county/city combos, the five worst are all located in PA.

Now let's take a look at the median household income deltas between the county/city combos.  This chart is structured the same as the high school graduation rate chart. Combos are sorted from those with the largest negative deltas at the top to those with the smallest at the bottom.

A quick investigation of the median income chart reveals a familiar pattern.  Counties in Pennsylvania appear to have a larger median income difference between county and city than comparable counties in other states.  In fact, three counties in PA (York, Lancaster, and Dauphin) have a median household income that is more than $20 K above the largest cities in those counties (York, Lancaster, and Harrisburg).

The next chart looks at the percent of population that is non-Hispanic white between county and city. As with the the two charts above, this one is structured with the largest negative difference at the top and the smallest at the bottom.

This chart reveals that PA counties--specifically south-central PA counties--appear to be both more segregated between county and city and to have more diverse cities than comparable counties.  On the segregation side York, Dauphin, and Lancaster counties have a greater than 40 percentage point difference between the percent non-Hispanic white in the county compared to the city.  On the other hand, the same counties have more diverse cities than comparable counties.  For example, Harrisburg's percentage of non-Hispanic white residents is 24.8%, and with 52.4% of its residents being African American, it is the only city in this sample that has a majority population that is something other than non-Hispanic white.  (Note: other cities have close to a plurality that isn't non-Hispanic white, but none have a majority.)

Taken together, the above three charts highlight four points of interest:

• Pennsylvania counties have a larger gap in high school graduation rates between county and city compared to other counties in different states.
• Pennsylvania counties have a larger gap in median household income between county and city compared to other counties in different states. 
• South-central PA counties are more segregated in terms of racial diversity between county and city than other comparable counties
• Cities located in south-central PA counties are more diverse than cities located in comparable counties

It's natural to ask why these trends appear in PA counties. It might even be reasonable to conclude that the large gaps in high school graduation rates and median household income indicate that Pennsylvania counties neglect their cities.  However, this would be premature without first exploring possible explanations for the trends.

Are the trends simply a function of county resources being applied to where the population is?  

One explanation for the trends highlighted above could be that the cities located in PA counties account for a much smaller percentage of total population than cities located the comparable counties of this analysis.  The bubble chart below shows the percentage of total county residents that live in the largest cities of the counties.

The bubble chart shows that cities in south-central PA counties represent a much smaller proportion of total county populations than the comparable counties. In fact, the total population of the five central PA cities (Lancaster, York, Harrisburg, Lebanon, and Carlisle) only represents 12 percent of the total population of the counties in which they are located. Compared to the 47 percent of total population that the nine other cities represent, the south-central PA cities make up a relatively small total population. This fact may help explain why we see large gaps in graduation rates and median income between the cities. If the cities of south-central PA represented a larger proportion of the area's population, it is likely that they would carry more weight when decisions are made about how to best allocate government resources.

How can the gap in graduation rates and median incomes be reduced?

Whatever the reason for the large gaps in high school graduation rates and median incomes between counties and cities of Lancaster and other central PA counties, it is worth exploring ways to reduce the deltas.  A reasonable approach might be to focus on improving the average educational attainment of the cities.  A population that is more highly educated is likely to be more qualified for jobs, which in turn will reduce the income gap.  A future post will explore the public high schools in Lancaster county to help shed some light on the performance gaps.