1. welcome introduction-handout - papachristos · sna workshop ~ yale university 11-12 august 2015...

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 1

Yale University

SOCIAL NETWORK ANALYSIS FOR CRIMINAL JUSTICE & VIOLENCE PREVENTION PRACTITIONERS

Yale Institute for Network Science 11-12 August 2015

Andrew V. Papachristos, Ph.D.

July 29th - 30th Yale Law School

Day 1

SNA Workshop ~ 2015

Learning Objectives

(1) Familiarize you with possibilities of SNA

(2) Expose you to different types of SNA data

(3) Get hands dirty with software and data

SNA Workshop ~ 2015

Roadmap ~ Day 1

(1) What is Social Network Analysis?

(2) Real World Examples of Applied SNA

(3) Introduction to Network Data

(4) Introduction to Network Software 1: RStudio

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 2

Section 1. What is Social Network Analysis?

SNA Workshop ~ 2015

‣  It’s a Small World

‣ Six Degrees of . . .

‣  It’s not what you know, but . . .

‣ The “good old boys” club

‣ The Strength of Weak Ties

‣ Bowling Alone

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 3

SNA Workshop ~ 2015

‣ The spread of disease, fashion, information, technology, and capital

‣ Political & Social Influence

‣ Attitudes, Opinions, & Behaviors

‣ Physical & Social Influence

‣ Friendships, Marriages, Relationships

‣ Human & Animal Societies

What predicts the risk of getting an STD?

Bearman, Moody, & Stovel 2004

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 4

Bearman, Moody, & Stovel 2004

What is a Social Network?

A FINITE SET (OR SETS) OF ACTORS AND THE RELATION

(OR RELATIONS) DEFINED ON THEM

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 5

2 Ties

1 Nodes

SNA Workshop ~ 2015

Edges

relations ties arcs

arrows

Nodes

actors dots

vertices

Examples

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 6

A Student Group

A Classroom

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 7

What is Social Network Analysis?

Social Network Analysis is the study of social relations and their influence on individual, group, and system behavior

Looking for Social Structure ~ regularities in patterns among units

1

2

SNA Workshop ~ 2015

Networks as: Dependent Variables

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 8

SNA Workshop ~ 2015

Networks as: Independent Variables

Criminal Justice Applications & Uses

SNA Workshop ~ 2015

The Study/Investigation of Criminal Groups 1

‣  How Cohesive are particular groups?

‣  What does a group’s structure look like?

‣  Who are important players?

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 9

SNA Workshop ~ 2015

SNA to study social contexts 2

‣  Peer influence on crime/delinquency

‣  “Landscape” of violence

‣  Social Control (or lack thereof)

SNA Workshop ~ 2015

Networks as conduit for diffusion 3

‣  Drugs

‣  Money

‣  Violence

‣  Information

‣  Guns

Gun Violence

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 10

Why guns?

•  Violence tends to occur between people who know each other

•  Gun violence is more concentrated within populations/places

•  Gun use is associated with peer influence

•  Guns are durable goods

Applications

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 11

(1)  Mapping Conflicts & Violence

Group Audits

Chicago, IL

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 12

New Haven, CT

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 13

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 14

(2) Identifying Group Structures

Boss

Underboss Underboss

St. Lt St. Lt St. LtSt. Lt

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 15

SNA Workshop ~ 2015

7-2 Gangster Disciples (Chicago, IL)

(3) Who’s At Risk of Being a Gunshot Victim?

Boston, MA

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 16

6 %

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 17

6 %

85 %

Newark, NJ

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 18

Newark, NJ

Newark, NJ

6% 65%

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 19

Chicago, IL

@AVPapachristosPapachristos, Wildeman, & Roberto 2015

•  6 % of total population

•  40 % of arrested population

•  70 % of all shootings

•  89% in a single network

Papachristos, Wildeman, & Roberto 2014

SNA Workshop ~ Yale University 11-12 August 2015

A.V. Papachristos 20

62.14

345.62

740.48

0

200

400

600

800

City Rate At Least 1 Arrest Arrest In Network

Non-Fatal Shooting Rate (per 100,000)

Associate

Shooting Victim

Co-Offending Tie

Family Tie

4 0 % O F A S S O C I A T E S A R E

V I C T I M S

T e x t