Wednesday, March 8, 2017

Assignment 3

Introduction

Council officials in Dane County, Wisconsin have noticed an increase in foreclosures between the years 2011 – 2012 – where a mortgagor fails to keep up with their payments, resulting in their property being repossessed. The aim of this report is to look for spatial patterns in the foreclosures, as well as predict whether or not there will be a further increase in foreclosures in 2013.




Figure 1 - Numbered Census Tracts in Dane County, Wisconsin, with test tracts outlined in red

Methodology

Using data showing the number of foreclosures per census tract within Dan County in 2011 and 2012, a map was created to show the areas of the county in which the number of foreclosures either increased or decreased. Preexisting data showing foreclosure numbers in both 2011 and 2012 was used to figure out how 2012 numbers differed from those observed in 2011.
Three test tracts were randomly chosen, from which the Z-scores of the number of foreclosures in both 2011 and 2012 were measured. The chosen tracts (122.01, 31 and 114.01) are highlighted above in figure 1.
A Z-score is used to locate the exact position of an observation on a standard deviation curve relative to the mean, so that exactly how many standard deviations away from the mean it lies can be known. This is useful, as from this probability can be derived of how likely this result was to occur. Z-score calculations can also be utilized to answer questions that help make predictions for the future: for instance, what number of foreclosures will be exceeded 50% of the time?


Results
Figure 2 - Changes in foreclosures, from 2011 to 2012, in Dane County census tracts.

 Figure 2 shows the changes in foreclosure numbers between 2011 and 2012 in Dane County. We can see that while there was a total of 1219 foreclosures in 2011, and 1316 in 2012, the number of foreclosures actually fell in many census tracts, particularly in Tract 113.02 in the north of the county, and Tract 5.04 in the center. Areas where the number of foreclosures fell are illustrated in blue on this map. There are however, many tracts where the number of foreclosures increased in this time, notably in the large Tract 129 in the north west and 119 in the east.
Figure 3 - 2011 Foreclosures by census tracts, Dane County, Wisconsin

If we compare these changes to the map in Figure 3, which shows the number of foreclosures by census tract in 2011, we can see that while some tracts that experienced a lot of foreclosures in 2011 saw an increase in 2012, this is not the case for all tracts – some of those, such as Tract 132 in the north of the county, has a high number of foreclosures in 2011 but saw a decrease in 2012. Furthermore, just to the east of Tract 132 is Tract 129, which in 2011 had a low number of foreclosures that rose sharply in 2012. These instances do seem to be anomalies, however, as the majority of tracts with higher numbers of foreclosures in 2011 saw an increase in 2012, as can be seen by comparing the smaller tracts in the center of the state from both Figure 2 and 3. Likewise, most of the tracts that had low numbers of foreclosures in 2011 saw a decrease in 2012, as illustrated by the tracts in the south west of the county.




Part 2 – Z-Score Results

2011
2012
Tract 122.01
-0.614
-0.636
Tract 31
1.437
0.576
Tract 114.01
2.384
2.695
Table 1 – Z-Score results for selected census tracts, for 2011 and 2012.

From the results above, we can see that for these three tracts, despite the overall rise in foreclosures within the county as a whole, the relative position on the standard deviation curve of these tracts has not changed drastically. The results for Tract 31 emphasis the fact that the rising number of foreclosures hasn’t affected all tracts in the county equally, as here the 2012 value of 24 the previous year dropped to 2012.
Based on the mean for 2012 across all of the census tracts of 9. 906 foreclosures, and the standard deviation of 8.776, there is a 70% probability that there will be over 16 foreclosures in any given county. There is a 20% chance that the number of foreclosures will be above 19. If this occurs, it is likely to do so in the tracts such as 120.01, just west of test tracts 31 and 114.01 (see figure 1). This tract can be seen to have a recorded a high number of foreclosures in 2011 from figure 3, and then proceeded to experience a large increase on this in 2012, as can be seen in figure 2. If this pattern of growth is to continue, it is likely that it would do so in this location.

Conclusion


From the data, we can see that growth in foreclosure numbers was not consistent across the county, but limited to certain tracts. The spatial pattern therefore seems weak, however if growing foreclosure numbers is to continue past 2012 there is a 70% chance of foreclosure numbers above 16 will be observed in the census tracts. It is clear from figures 2 and 3 the number of foreclosures in tracts are variable in most circumstances, however notable areas such as tract 120.01 have experienced high growth on already relatively high numbers of foreclosures. This could be due to changing economic circumstances after the 2008 financial crash, which has caused many redundancies and wage cuts which could explain why the numbers of foreclosures are so variable and not confined to one area of the county – perhaps a more deprived area, for instance.