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

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

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

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

Environmental influences Segmented years for analysis 2003-2005: Beginning of stop and frisk 2006-2009: Heightened frequency of stops 2010-2011: Initial controversy over release of taped recordings of police instructions to target black individuals 2012-2013: Heightened visibility and controversy of stop and frisk activity. Marches and social protests begin to occur 2014-2016 : Oversight and court cases impact the process of stop and frisk

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

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

Logistic regression in R Arrest (Dependent) ~ Frisk and Search (Independent) 2014 - 2016: Frisk has inverse relationship with an arrest Potentially inaccurate frisk procedures Frisk (Dependent) ~ Age, Sex, and Race (Independent) 2006 - 2009: Black as race has inverse relationship with frisk Police target individuals based on biases, no outcomes to stops 2014 - 2016: 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. 2014 - 2016, 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) 2014 - 2016: 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) 2006 - 2009: Black as race has inverse relationship with frisk Police target individuals based on biases, no outcomes to stops 2014 - 2016: 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. 2014 - 2016, 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

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 2014 - 2016 data was removed as a less impacting variable Race: Variety of changes through models of different years 2014 - 2016 only race variable kept was inverse relationship with Asians and use of force 2006 - 2011 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 2014 - 2016 data, where it was removed as a less impacting variable 2014 - 2016 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 2006 - 2011

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 2014. 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

Questions?

Outside Sources https://www.policeone.com/legal/articles/2774108-Cop-who-made-tapes- accuses-NYPD-of-false-arrest/ http://www.reuters.com/article/us-usa-newyork-march- idUSBRE85G0A920120617 http://www.nytimes.com/2013/08/13/nyregion/stop-and-frisk-practice- violated-rights-judge-rules.html