Theme

Computer are good at consuming, producing and processing data

Humans are good at consuming, producing and processing stories

For data to be useful to humans, we need tools for telling stories that involve code and data

Illustration

Data and code



In [1]:

    
%matplotlib inline
import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
import seaborn as sns



In [2]:

    
df = pd.read_csv('data/police_locals.csv')
df = df.replace('**',np.nan)
df['all'] = df['all'].astype('float')
df['white'] = df['white'].astype('float')
df['non-white'] = df['non-white'].astype('float')
df['black'] = df['black'].astype('float')
df['hispanic'] = df['hispanic'].astype('float')



In [3]:

    
df.head()









    Out[3]:






  
    
      
      city
      police_force_size
      all
      white
      non-white
      black
      hispanic
    
  
  
    
      0
          New York
       32300
       0.617957
       0.446387
       0.764419
       0.770891
       0.762861
    
    
      1
           Chicago
       12120
       0.875000
       0.871963
       0.877400
       0.897406
       0.839827
    
    
      2
       Los Angeles
       10100
       0.228218
       0.152778
       0.263848
       0.387387
       0.217680
    
    
      3
        Washington
        9340
       0.115632
       0.056774
       0.157365
       0.170189
       0.089888
    
    
      4
           Houston
        7700
       0.292208
       0.173735
       0.399258
       0.366379
       0.457143



In [4]:

    
len(df)









    Out[4]:





76



In [5]:

    
df[['white','non-white']].describe()



In [6]:

    
sns.set_context("talk")
sns.set_style("whitegrid")
sns.boxplot(df[['white','non-white']]);

Story

This data comes from an article published on 538 on August 20 entitled, Most Police Don’t Live In The Cities They Serve. From the article:

In Ferguson, Missouri, where protests continue following the shooting of a teenager by a police officer this month, more than two-thirds of the civilian population is black. Only 11 percent of the police force is. The racial disparity is troubling enough on its own, but it’s also suggestive of another type of misrepresentation. Given Ferguson’s racial gap, it’s likely that many of its police officers live outside city limits.

The above dataset, published by 538 on this GitHub repository contains the fractions of police officers who live within the city they serve, for different races of police officers for 75 cities across the U.S. Now we can develop a story around that data:

On average, only a very small fraction ($\approx 35\%$) of white police officers live in the cities they serve.
On average, non-white police officers ($\approx 49\%$) are more likely to live in the cities they serve.
There is a significant spread ($\sigma\approx 25\%$) across individual cities.
For issues of racial justice, it could be useful to have more police officers live in the cities they serve.

Without the story, the data doesn't mean much to us.

	white	non-white
count	76.000000	76.000000
mean	0.348386	0.486143
std	0.240522	0.252310
min	0.026667	0.076923
25%	0.151914	0.302225
50%	0.293472	0.473922
75%	0.502404	0.669569
max	0.962963	0.956522

	city	police_force_size	all	white	non-white	black	hispanic
0	New York	32300	0.617957	0.446387	0.764419	0.770891	0.762861
1	Chicago	12120	0.875000	0.871963	0.877400	0.897406	0.839827
2	Los Angeles	10100	0.228218	0.152778	0.263848	0.387387	0.217680
3	Washington	9340	0.115632	0.056774	0.157365	0.170189	0.089888
4	Houston	7700	0.292208	0.173735	0.399258	0.366379	0.457143