Investigating Dog Bites in New York City with SAS
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As the proud human “parents” of a Cavalier King Charles Spaniel, my wife and I naturally adore our dog. He’s very friendly with humans and sociable with other dogs and we trust him completely.
However, the fact is that every day people are bitten by dogs and in the wake of a spate of attacks in 1991, the UK parliament passed the Dangerous Dogs Act, which banned the keeping of any dog which is dangerously out of control along with four specific types of dog without an exemption from a court. These are the banned types:
- Pit Bull Terrier
- Japanese Tosa
- Dogo Argentino
- Fila Brasileiro
The ban covers not only pure breed dogs but crossbreeds. The decision as to whether a dog is a banned type must be made by an experienced police dog handler. The ban mainly affected Pit Bulls and was and still is controversial, with former and current owners claiming Pit Bulls are not inherently dangerous as is implied by the act.
I was interested, therefore, to discover that the New York City Data Portal contains data on dog bites in the “Big Apple,” and I decided to use SAS University Edition to determine whether or not there was cause for concern over attacks by Pit Bulls.
Get the Data
The portal allows you to download data in a number of different formats. I chose to download a CSV file.
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Getting the Data Ready
I used PROC Import to create a SAS data set from the CSV file. I used quite a large value for the GUESSINGROWS parameter as, although it makes the import slower, I find that otherwise text fields are very often truncated. Here is the code:
filename dogbites '/folders/myshortcuts/Dropbox/DOHMH_Dog_Bite_Data_2019.csv';
proc import datafile=dogbites
dbms=csv
out=dog_bites
replace;
getnames=yes;
guessingrows=4000;
run;
This is what the imported file looks like:
The Results
After sorting the file I ran PROC Means to count the number of bites that occurred for each breed. I then sorted the output from that and ran PROC SGPlot to create a horizontal bar chart of the 10 breeds responsible for most bites. This is the code, followed by the chart:
proc sort data=dog_bites;
by breed;
run;
proc means data=dog_bites noprint n;
by breed;
output out=bitefreq n=numbites;
run;
proc sort data=bitefreq;
by descending numbites;
run;
ods graphics / reset imagemap;
title1 'Number of Dog Bites in New York City 2015-2017';
title2 'Top Ten Frequency by Breed (Excludes Missing Values)';
footnote1 j=r 'Data from https://opendata.cityofnewyork.us/';
proc sgplot data=bitefreq(obs=10);
hbar breed / response=numbites
categoryorder=respdesc
dataskin=pressed fillattrs=(color=vpab)
datalabel
tip=(numbites)
tiplabel=("Number of Bites");
xaxis label="Number of Dog Bites";
yaxis label="Breed" fitpolicy=none;
run;
Pit Bulls are the outlier
We can see that Pit Bulls are responsible for by far the largest number of bites per breed during this period - 1,921 against 364 for the next breed on the list, the Shih Tzu. Moreover, this is even more dramatic if you look a little farther down the list with American Pit Bull Terrier / Pit Bulls and American Pit Bull Mix / Pit Bull Mix also in the top 10.
I decided to group all Pit Bull and Pit Bull mixes together and match them against the number of bites for all other breeds. Firstly, I created a format to help in the final chart display and wrote a data step to classify all breed entries as either "Pit Bull Type" or "Other":
proc format;
value breed
0="Other"
1="Pit Bull Type";
run;
data dog_bites_std;
format pit_bull_type breed.;
set dog_bites;
if find(upcase(breed),"PIT BULL") or
find(upcase(breed),"PITBULL") then pit_bull_type=1;
else pit_bull_type=0;
run;
As before, I then sorted the file, ran PROC Means to aggregate the result and PROC SGPlot to produce a bar chart:
proc sort data=dog_bites_std;
by pit_bull_type;
run;
proc means data=dog_bites_std noprint n;
by pit_bull_type;
output out=bitefreqtype n=numbites;
run;
ods graphics / reset imagemap;
title1 'Number of Dog Bites in New York City 2015-17';
title2 'Pit Bull Types v Others';
footnote1 j=r 'Data from https://opendata.cityofnewyork.us/';
proc sgplot data=bitefreqtype(obs=10);
hbar pit_bull_type / response=numbites
categoryorder=respdesc
dataskin=pressed fillattrs=(color=vpab)
datalabel
tip=(numbites)
tiplabel=("Number of Bites");
xaxis label="Number of Dog Bites";
yaxis label="Dog Type" fitpolicy=none;
run;
From this chart we know that Pit Bulls and Pit Bull crossbreeds were responsible for 2,839 bites against 7,441 for all other breeds combined (over 25% of the total bites).
Unfortunately, we don't have a record of the number of dogs of each breed in New York during this period that we could use to determine a "bite ratio." There is a file of currently licensed dogs on the portal, but it doesn't give us any way to account for fluctuations in numbers over the two-year period. I was reluctant, therefore, to include it in my analysis, but the figures we have do indicate Pit Bulls being responsible for a very high percentages of attacks, giving at least some cause for further investigation.
Now it's your Turn!
Did you find something else interesting in this data? Share in the comments. I’m glad to answer any questions.
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