**Note: This blog post will make several references to Detroit’s Master Plan Neighborhoods. If you would like to view a reference map of these neighborhoods, please click here.
What is Average Residential Structure Condition?
The Motor City Mapping project is a survey of Detroit properties that was completed in early 2014, providing information on some 380,000 individual parcels in the city. This survey recorded whether each parcel had a structure on it, the condition of the structure, and whether or not the building was occupied. This information has also been summarized for the roughly 880 census block groups in Detroit (each block group includes several contiguous blocks).
Much of the data from Motor City Mapping can be compared to the 2009 Detroit Residential Parcel Survey (DRPS) conducted by Data Driven Detroit and its partners. Though the earlier survey was limited to 1-4 unit residential properties, it is possible to compare the structural condition data for about 840 block groups at two points in time, from 2009 to 2014. For every structure surveyed, the property’s condition was assigned a value from 1 to 4 with 1 indicating the best possible condition. To account for differences in size of block groups, we created a weighted average of block group condition by summing condition values for all residential structures in the block group and then dividing the total by the total number of residential structures in the block group. Values closer to 1 indicate stronger average condition, while a value closer to 2 (or even below 2) indicates an area with much poorer structural condition.
Average Residential Structure Condition in 2009
In general, the condition of residential structures is related to their age. Many block groups with the strongest average condition were found at the outer edges of the city, while many of those with the poorest-condition housing stock were located in older neighborhoods just outside of the core of the city (Figure 1). An exception is evident in northwest Detroit, where the Brightmoor neighborhood stands out as a pocket of blight located between more stable areas. This may be due to the wood-frame, 1950’s housing construction that once abandoned, has decayed at a faster rate than in other areas of the city where the construction typically incorporates greater amounts of stone or brick.
With limited exceptions, the area south of the Ford Freeway (Interstate 94) included very few block groups in the highest two ranges. The few such neighborhoods with better average condition ratings included the Far East Side (particular the Finney Master Plan Neighborhood), some areas of the East Riverside and Indian Village neighborhoods, and portions of Corktown, Hubbard Richard, Vernor/Junction, and Springwells in Southwest Detroit.
There was typically a gradual transition between the average condition ratings in adjacent neighborhoods. That is, neighborhoods in the top range were typically bordered by neighborhoods in the first or second categories. There were, however, a few instances where block groups with the strongest average condition were adjacent to those with the weakest average condition. Particularly prominent examples existed on either side of Woodward north of 7 Mile, as well as some of the block groups on the borders of the Brightmoor and Rosedale neighborhoods.
Average Residential Structure Condition in 2014, Compared to 2009
By the time that the Motor City Mapping Survey took place, conditions had changed considerably in many portions of the city. The average condition rating for each of the block groups in 2014 is shown in Figure 2. While the overall geographic concentrations of good and poor quality housing are similar to 2009, there are some important differences. Southwest Detroit has seen a decline in housing condition, and the blight that was evident around Brightmoor in northwest Detroit and the Gratiot-McNichols area in northeast Detroit seems to be spreading. The Rosedale and Cerveny/Grandmont Master Plan Neighborhoods (which contain Grandmont-Rosedale) are no longer solidly in the top range of block groups, and similar declines can be seen in the Finney Master Plan Neighborhood, which includes East English Village. Both of these areas have resisted the encroachment of nearby blight, but these data indicate that even traditionally-stable neighborhoods are experiencing some degree of erosion.
There was substantial movement between the categories defined in 2009 and 2014, as shown in Table 1. The top two ranges contained a net total of 79 fewer areas, a decrease of nearly 19%. The growth in the range with the weakest average condition – an increase of 70 block groups – is particularly concerning, and indicates that an increasing number of neighborhoods across the city may be entering steeper spirals of structural decline.
Absolute Changes in Residential Condition from 2009 to 2014
The two surveys recorded a small overall decline in the average residential condition rating for the city of Detroit, from an average rating of 1.23 to 1.27 in 2014. As shown in Figure 3, more than 500 block groups observed declines in average condition, while 315 saw an improvement or no change. Much of the improvement occurred on the East Side, including some of the neighborhoods with the poorest structural conditions in 2009. Considering that many of these areas have been identified by city planning processes as high-vacancy, it is likely that much of the observed increase is due to demolition of blighted structures, rather than as a result of new construction or rehabilitation.
Studying the data based on the ranges defined in 2009 reveals additional insights. Most of the block groups in that were in the top category in 2009 experienced a decline in average condition rating; only one in eight showed improvement. In contrast, over 60% of the neighborhoods in the weakest category in 2009 observed an improvement in average condition. In 2009, 25% of block groups had 95%+ of structures rated in good condition. By 2014, this number had declined by 20%, and the number of block groups where less than two-thirds of all structures received a good rating increased from 202 to 269. The average score in the top quarter of block groups declined by 0.042 while the average in the bottom quarter showed an improvement of 0.036.
Although five years is a relatively short time in the life of a city, there has been a noticeable decline in the average condition of residential structures since 2009. The areas where the best-quality housing predominates are shrinking, while the pockets of blight are growing. While there are large areas where the average structural condition rating has improved, this appears to have most often been the result of the demolition of the poorest-condition homes. In general, the changing landscape of average residential structure condition illustrates a concerning trend in the city that must be reversed if Detroit’s neighborhoods are to have any chance at recovery.
Next week, City of Change will examine occupancy in Detroit’s neighborhoods, and the changing patterns of where the city’s residents call home.
The Motor City Mapping data are available in their raw format on the Data Driven Detroit (D3) Open Data Portal – http://portal.datadrivendetroit.org.