Advancing Human Trafficking Prevalence …...From Developing and Field Testing a Hidden Population Method Acknowledgement This work was supported by Grant #2015-MU-MU-0003 awarded

National Academy of Sciences, Engineering, Medicine:

Workshop on Estimating the Prevalence of Human Trafficking in the United States

April 9, 2019

Michael Shively; Ryan Kling; Amy Berninger; Lauren Christopher; Brenda Rodriguez; Melissa Nadel

Advancing Human Trafficking

Prevalence Estimation: Key findings

From Developing and Field Testing a

Hidden Population Method

Acknowledgement

This work was supported by Grant #2015-MU-MU-0003 awarded by the

National Institute of Justice, Office of Justice Programs, U.S.

Department of Justice to Abt Associates. Points of view in this

presentation are those of the authors and do not necessarily represent

the official position of the U.S. Department of Justice. Any errors or

omissions are the responsibility of the project team.

Copyright © 2019, Abt Associates, All Rights Reserved

2

Presentation Overview

• Project Objectives & Design

– Develop method of producing county-level estimates of human trafficking

prevalence

– Data collection & analysis

• Key Findings

– Feasibility (results and lessons learned from field test)

– Identifying victims (via responses to survey)

– Victim prior contacts with systems & services

– Prevalence estimates (extrapolating from samples to county)

• Conclusions and Recommendations

• Q&A

Research Questions

1. What is the prevalence of human trafficking victimization within jail, shelter, and hospital emergency department populations?

– Sex and labor trafficking– Males and females

2. What is the estimated number of victims within a county?

3. What is the extent of victim prior contact with local service providers and justice system?

4. Are the methods feasible to implement, and suitable for future adaptation, broader use?

Prevalence Estimation Method

• Estimates number of individuals that have ever been trafficked, within a county during1-year span.

• Scientifically sound estimates possible when:

– Trafficked individuals can be identified within representative samples.

– The probability of any individual appearing in a screened population can be calculated

• Extension of methods developed over past 30 years, e.g.

– Annual visits to public parks (National Parks Service)

– Chronic drug users in a community (Rhodes, Kling, & Johnston)

5COMPANY CONFIDENTIAL ©

Method Requires

1. Survey to establish victimization rate within samples.

Hospital emergency department Homeless shelter Jail booking facility

2. Data to calculate probability of individuals appearing in surveyed facilities.

3. Data on prior contacts with facilities (to avoid double-counting).


Selected Counties

• Site #1: Hennepin County, MN

• Site #2: Unnamed (SW border region).

• Selections based on combination of size, region,

system infrastructure, willingness to participate

Study Implementation

• Developed questionnaire

– Trafficking Victim Identification Tool (TVIT) impractical for rapid screening.

– Adapted version: 7 items, closed ended responses. – Added “calendar follow-back” component.

• Selected and developed partnerships with:

1. Booking facility (Hennepin County Sheriff’s Office)2. Shelters (Salvation Army, Catholic Charities)3. Emergency medical facility (Hennepin County Medical

Center)

Survey: Victimization Screener

Survey: Calendar Follow-Back

Asks about contacts in prior 12 months with:

Key Findings - Feasibility

• Implementation was fully successful in one county

– Completed survey in all targeted data collection sites.

– Substantial samples in short timeframes.

• Local governments could obtain larger samples at lower

costs.

– Respondents agreed to be interviewed

• 591 respondents

• 65% Agreement Rate

– Prevalence rates high enough for samples to support

estimation with modest sample sizes

Key Findings - Victims Identified in Sample

7.1% had been victims of human trafficking, based on survey responses & conservative definitions.

Key Findings - Victim Prior Contacts

100% of identified victims had contacts with healthcare, social service, justice systems in prior 12 months.

Service/Agency

Trafficked

(N=42)

Percent N

Urgent Care/ED* 83.9 % 32

Welfare (TANF, SNAP, or WIC)*** 66.0 % 27

Mental Health Services*** 57.6 % 24

Church or Faith-Based Services*** 55.4 % 26

Jail/Prison** 43.5 % 19

Hospital Overnight 41.3 % 14

Treatment Center*** 35.7 % 14

Homeless Shelters 34.9 % 18

Child Protective Services*** 29.1 % 13

Legal Aid** 25.0 % 12

Victim Services*** 25.0 % 9

ICE 2.2 % 1

Reproductive Health Center 1.7 % 1

Other Services** 25.2 % 13

Key Findings - Estimated Number of Ever-

Trafficked Individuals in One County


Estimate Type

Jail Venue

Hospital EDVenue

Shelter Venue Total

Jail 4,385 -401 * NA

Hospital ED -208 3,534 * NA

Shelter -3 -19 54 NA

Total 4,174 3,114 54 7,341

* Estimate under review

At end of this presentation, can walk through the estimation method. For now:

Conclusions

• Method is feasible, capable of producing sound estimates of both sex & labor trafficking, among both men & women, in diverse populations.

• Victimization prevalence was greater than expected, and skewed toward labor trafficking.

• Data on prior contacts suggests that routine screening would support earlier detection & response.

• Need for brief, validated screening instruments & protocols.

Next Steps, Q&A

Refine county-level estimates

Disseminate methods, findings

Adapt, replicate

Assess potential for broader application

Questions, Discussion

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abtassociates.com

Contact

Michael Shively Ryan Kling

Senior Associate Principal Associate

[email protected] [email protected]

+1 617-520-3562 +1 617-349-2460

Addendum

Overview of HPE Estimation


Following a Hidden Population


H1

population



H1 H2

population

visit venue

in the

sampling

year



H1 H2 H3

population

visit venue

in the

sampling

year

in venue

when we

draw

sample



H1 H2 H3 H4

population

visit venue

in the

sampling

year com

ple

ted

surv

ey

in venue

when we

draw

sample



H1 H2 H3 H4

population

visit venue

in the

sampling

year com

ple

ted

surv

ey

in venue

when we

draw

sample

W3



H1 H2 H3 H4

population

visit venue

in the

sampling

year com

ple

ted

surv

ey

in venue

when we

draw

sample

W2W3



H1 H2 H3 H4

population

visit venue

in the

sampling

year com

ple

ted

surv

ey

in venue

when we

draw

sample

W1

W2W3

Weights to Build a Community

Estimate

• W3 – Survey sample weight to go from the sample to the population during our survey period

• W2 – Weights the survey period to a year (i.e. this equals 26)

• W1 – The inverse of the estimated number of times an individual visits our sample venue


Estimating W1

• For the jail and emergency department, negative binomial regression

– Dependent variable is the number of times vising the jail or ED

– Independent variables include demographics, other individual characteristics

– Accounts for time on the street in past year

• For the shelter, OLS regression of proportion of year in the shelter


Actual and Predicted Number

of Visits to Jail in the Past Year


Actual Predicted

Sample Contribution from two

Booked Individuals


Type Individual 1 Individual 2

Individual is Trafficked 1 1

W3 (Sample Weight) 7.34 8.17

W2 (Inflate to Year) 26 26

W1 (Predicted Number of Bookings in Year) 0.84 3.17

Inverse of W1 1.18 0.32

Total = W3 x W2 x (1/W1) 225.84 66.98

A Complication: Trafficked

Individuals Appear at Multiple Venues


0

2

4

6

8

10

Jail EmergencyDepartment

Shelters

Freq

ue

ncy

of

Ind

ivid

ual

sNumber of Venues Visited by Venue Sampled for

Trafficked Individuals

One Two Three

Accounting for Double Counting

• We can estimate the probability of appearing in

multiple venues

• Once calculated, we can subtract out the

appearance of appearing at the other venue to avoid

double-counting

• Prefer to count someone where they were sampled


Estimated Number of Ever-

Trafficked Individuals


Estimate Type Jail Venue

Emergency Department Venue

Shelter Venue Total

Jail 4,385 -401 * NA

Emergency Department

-208 3,534 * NA

Shelter -3 -19 54 NA

Total 4,174 3,114 54 7,341

* Estimate under review

abtassociates.com

ContactMichael Shively Ryan Kling

Senior Associate Principal Associate

[email protected] [email protected]

+1 617-520-3562 +1 617-349-2460

Documents

Advancing Human Trafficking Prevalence …...From Developing and Field Testing a Hidden Population Method Acknowledgement This work was supported by Grant #2015-MU-MU-0003 awarded