1. Stop , Question and Frisk Statistical Analysis
Presented by James Dodson, Richard Koch, Cong Liu, Stephanie Nguyen, and Lei Yang

2. Questions to address for police commissioner
Is Stop and Frisk decreasing the guns or other types of weapons in this period?
Is Stop and Frisk decreasing crime in general?
Are officers showing a bias during the Stop and Frisk stops?
Overall, predicting that Stop and Frisk is not successful due to low average proportion of success
Overall, predicting that crime is not decreasing
Overall, predicting that biases are held against Black individuals due to large population of stops

3. Our approach to the issue
Visualization Assignment to guide initial predictions and steer hypothesis testing
JMP for clustering for initial data mining and additional analysis
R Programming to review, clean, and analyze data
Identify and evaluate overall dependent and independent variables in dataset
Convert all variables to binary for logarithmic analysis
Descriptive statistics to evaluate year over year changes
Logistic regression to evaluate efficiencies and biases within years
Stepwise regression to evaluate biases

4. What data is considered
Searched
Frisked
Arrested
Summons issued
Contraband found
Weapon found
Reason For Stop
Reason for Frisk
Basis for Search
Force Used
Sex
Race
Age

5. Environmental influences
Segmented years for analysis
: Beginning of stop and frisk
: Heightened frequency of stops
: Initial controversy over release of taped recordings of police instructions to target black individuals
: Heightened visibility and controversy of stop and frisk activity. Marches and social protests begin to occur
: Oversight and court cases impact the process of stop and frisk

6. Clustering and general predictions
Race impacts whether or not arrest occurs
Younger individuals more likely to be arrested

7. Summary statistics in R
Program more effective in later years
2013 court ruling heavy impacts results
Average stops are males in mid- late 20s
Program gets more effective in later years
Arrests
Contraban
Weapons
Not Summons
2013 court ruling - Requires stop and frisk to have rules and not freedom of police officers
Lessened stops
Significantly more arrests
Mean age of individuals in stops through all years in late 20s
Males range from 86% - 93% of population
Graph:
Higher arrests, contraband found, weapons found, frisks, and searches in 5th group (Regulation)
Not better in summons (progressively worse through the years)
Use of force is proportionally the highest in final - during years of active protesting, it was at its lowest
Males are growing proportion of stops throughout the years
Asians are being targeted progressively more through the years
Race of black are increasing/staying the same as a proportion
White hispanic is decreasing
American Indians are staying about the same, as are Black Hispanics
White fluctuates between 9-11% throughout the years

8. Logistic regression in R
Arrest (Dependent) ~ Frisk and Search (Independent)
: Frisk has inverse relationship with an arrest
Potentially inaccurate frisk procedures
Frisk (Dependent) ~ Age, Sex, and Race (Independent)
: Black as race has inverse relationship with frisk
Police target individuals based on biases, no outcomes to stops
: Black as race has low P Value, not impactful to the model
Outside forces cause officers to use less biases in stops
Use of Force (Dependent) ~ Age, Sex, and Race (Independent)
All data: Males have direct relationship with use of force, age has inverse relationship.
, Black as race has low P Value, not impactful to the model
All Data: Hispanics have direct relationship with use of force, does not change
Only including Extremely low P value and residual deviation is far from the null in ANOVA
Arrests - More frisks used in previous years
Arrest (Dependent) ~ Frisk and Search (Independent)
: Frisk has inverse relationship with an arrest. If frisked, decreased odds of arrests
Search has direct.
Potentially inaccurate frisk procedures
Remainder of years have direct relationships between arrests and frisks/searches
Frisk (Dependent) ~ Age, Sex, and Race (Independent)
: Black as race has inverse relationship with frisk
Police target individuals based on biases, no outcomes to stops
: Black as race has low P Value, not impactful to the model
Outside forces cause officers to use less biases in stops
Use of Force (Dependent) ~ Age, Sex, and Race (Independent)
All data: Males have direct relationship with use of force, age has inverse relationship.
, Black as race has low P Value, not impactful to the model
All Data: Hispanics have direct relationship with use of force, does not change

9. Stepwise Regression
Force Use (Dependent) ~ All stop reasons, Age, Sex, and Race
Outcomes:
Age: removed from all models
Males: Direct relationship with use of force with most years
data was removed as a less impacting variable
Race: Variety of changes through models of different years
only race variable kept was inverse relationship with Asians and use of force
race of Black and Hispanic have direct relationships with use of force
Force Use (Dependent) ~ All stop reasons, Age, Sex, and Race
To identify the most impacting variables to the model. Some reasons for stop, such as violent crimes, could be assumed to result in force more often
Age removed from all models
Males: Direct relationship with use of force until data, where it was removed as a less impacting variable
only Race variable kept was inverse relationship with Asians. Remainder of impacting variables were reasons for stop.
Race of Black and Hispanic have direct relationships with Force Use from

10. Answers for police commissioner
Is Stop and Frisk decreasing the guns or other types of weapons in this period?
Accuracy in arrests, contraband, and weapons increased greatly at However, only 21% of stops ended in arrest in 2016.
Is Stop and Frisk decreasing crime in general?
As most stops result in misdemeanor crimes. When contrasted with NYC misdemeanor crimes overall, crime did not decrease higher than years prior to stop and frisk.
Are officers showing a bias during the Stop and Frisk stops?
Officers show bias in early to middle years, but lessen as increased public exposure and court rulings impact procedures

11. Questions?

12. Outside Sources
accuses-NYPD-of-false-arrest/
idUSBRE85G0A
violated-rights-judge-rules.html