Evidence-based Synthesis Program 

(ESP)

Th Li R di The Literature 

Regarding

Homelessness among Veter

A Critical Review of the Eviden

Portland VA Medical Center Portland VA Medical Center

May 23, 2011 May 23, 2011
Evidence-based Synthesis Program 

(ESP)

Ak ld c

know

l

edgements

Co-Authors/Presenters

H d Blh M S

Reviewers

o

Howard

B

als

hem, 

M.S. M C i

o Vivian Christensen, Ph.D.o Stephen Metraux, Ph.D

o Thomas O’Toole M D

o

Mary 

Cunning

o Amy Kilbourneo John Kuhn

o Thomas O Toole, 

M.D. o Stephen Metra

o Anais Tuepker, Ph.D.o Devan Kansagara, M.D.

o Stephen Metra

o Thomas O’Tooo David Smelson
Evidence-based Synthesis Program 

(ESP)

Di l sc

losure

This report is based on research conducted by the Evidence-basSynthesis Program (ESP) Center located at the Synthesis Program (ESP) Center located at the Portland VA Med

Portland VA Med

funded by the Department of Veterans Affairs, Veterans Health Administration, Office of Research and Development, Health SeResearch and Development. The findings and conclusions in th

document are those of the author(s) who are responsible for its the findings and conclusions do not necessarily represent the viDepartment of Veterans Affairs or the United States governmenTherefore no statement in this article should be construed as aTherefore, no statement in this article should be construed as a

position of the Department of Veterans Affairs. No investigatoraffiliations or financial involvement (e.g., employment, consultahonoraria, p p , p y, g 

 stock ownershi

p or o

ptions, ex

pert testimony,

grants 

received or pending, or royalties) that conflict with material prethe report.
Evidence-based Synthesis Program 

(ESP)

VA Evidence-b d h i( 

base

d Synt

hes

is 

(ES

Program Overview

• S d b VA Offi f R&D d HSR&D Sponsore

d

by VA Office o

f R&D an

d HSR&D.

• Established to provide timely and accurate 

syntheses/reviews of healthcare topics identified b

cli i i d li li

nicians, managers an

d poli

c

y-mak th 

kers, as they wo

improve the health and healthcare of Veterans. 

• Builds on staff and expertise already in place at the 

Evidence-b d i ( )d i d

base

d Practice Centers 

(EPC

)

designate

d

Four of these EPCs are also ESP Centers: 

o Durham VA Medical Center; VA Greater Los Angeles He

System; Portland VA Medical Center; and Minneapolis VCenter.
Evidence-based Synthesis Program 

(ESP)

• P id id th i t t li i l 

Provides evidence syntheses on impor

tan

t cli

nical 

topics relevant to Veterans, and these reports help:

o develop clinical policies informed by evidence, 

o the implementation of effective services to improve 

the implementation of effective services to improve 

outcomes and to support VA clinical practice guideperformance measures, and 

o guide the direction for future research to address g

guide the direction for future research to address g

clinical knowledge.

• Broad topic nomination process – e.g. VACO, VISNs

facilitated by ESP Coordinating Center (Portland) thfacilitated by ESP Coordinating Center (Portland) th

online process: 

http://www.hsrd.research.va.gov/publications/esp/TopicNomin
Evidence-based Synthesis Program 

(ESP)

• St i C itt ti h d 

Steering 

Committee representing researc

h an

d ope

(PCS, OQP, ONS, and VISN) provides oversight and program direction.

• T h i l Ad i P l (TAP) Tec

h

nical Ad

visory 

Panel (TAP)

o Recruited for each topic to provide content expertio Guides topic development; refines the key questiono Reviews data/draft report Reviews data/draft report.

• External Peer Reviewers & Policy Partners

o Reviews and comments on draft report

•

Fi l d b i d di 

inal reports poste

d on VA HSR&D we

b

site an

d diss

widely through the VA. 

http://www.hsrd.research.va.gov/publications/esp/reports.
Evidence-based Synthesis Program 

(ESP)

Current Report

A C i i l R i f h Li R A

C

r

i

t

ica

l

Rev

iew o

f t

he Literature 

R

e

g

Homelessness among Veterans

(April 2011) (April 2011)

Full-length report available on ESP website:

http://www.hsrd.research.va.gov/publications/esp/reports.
Evidence-based Synthesis Program 

(ESP)

Ot

her Recent Reports

• Veteran Homelessness: A Supplemental Report to the 2009 

Homeless Assessment Report to Congress 

• Community Homelessness Assessment, Local Education, an

Networking Group (CHALENG) for Veterans Report

• Opening Doors: the Federal strategic plan to prevent and e

homelessness

• Annual Homeless Assessment Report (AHAR) Annual Homeless Assessment Report (AHAR)• State of Homelessness in America• Homelessness: A Common Vocabulary Could Help Agencie

Collaborate and Collect More Consistent Data Collaborate and Collect More Consistent Data
Evidence-based Synthesis Program 

(ESP)

Oth i ifi her Sig

nificant Reports

• Vital Mission: Ending Homelessness Among Veterans• Veteran Homelessness: CRS Report for Congress• H l P d th P l Th S Homelessness: 

Programs and the 

People They 

Serve
Evidence-based Synthesis Program 

(ESP)

Overvi f d’ i iew o

f To

day

’s Presentat

io

• Objectives• Background: Why is this topic of interest• Scope of the review• Findings

• Prevalence• Risk Factors• Military

-related factors related factors

• Incarceration• Limitations of the literature

• Future Research Future Research
Evidence-based Synthesis Program 

(ESP)

Obj i ect

ives

• Learn about the prevalence of homelessness among • Learn about risk factors for homelessness• L b t i k f t ifi t V t Learn a

bou

t ris

k

fac

tors specific 

to 

V

e

terans 

• Understand the limitations of the literature and rese

homelessness

• Initiate a discussion about opportunities for future 

on homelessness among Veterans on homelessness among Veterans
Evidence-based Synthesis Program 

(ESP)

Back dgroun

d

• Objectives of review

• Part of national effort to end homelessness among Vet

• Sco

pe of Review

• Veteran homelessness• Personal characteristics of the homeless• Personal risk factors for homelessness

• Outside of Scope

• Structural risk factors

• I t ti n

terventions
Evidence-based Synthesis Program 

(ESP)

Structura

l Factors

• Lack of Affordable Housing• Employment-related issues• D i titl t t Decreases in entitlemen

t paymen

t

s
Evidence-based Synthesis Program 

(ESP)

Meth do

d

s

• Topic Development

• National Center for Homelessness Among Veterans

•

Technical Experts

• Search

• Major bibliographic databases

• Snowball search• Gray literature

• Study selection

• Broad selection criteria – very inclusive

• Synthesis

•

Qualitative

• Peer review
Evidence-based Synthesis Program 

(ESP)

K Q ti 1 Key 

Question 

1

• Key Question 1A: What is the prevalence and incide

hl ? ome essness among Veterans

?

• Key Question 1B: How has the prevalence and incid

homelessness among Veterans changed over time? homelessness among Veterans changed over time?

• Key Question 1C: How prevalent are psychiatric illn

substance abuse and chronic medical illness among substance abuse, and chronic medical illness among

homeless Veterans?
Evidence-based Synthesis Program 

(ESP)

K Q ti 2 Key 

Question 

2

• Key Question 2A: Which risk factors are associated 

hl hl homelessness or a return to 

homelessness among V

How do these risk factors differ from non-Veteran populations?

• Key Question 2B: Have risk factors for homelessnes

Veterans changed over time?
Evidence-based Synthesis Program 

(ESP)

K Q ti 3 & 4 Key 

Questions 

3

&

4

• Key Question 3: Are there factors specific to military 

th i h i k fh l i h i 

hat increase t

he ris

k o

f

homelessness, or is t

he inc

risk a marker for pre-military comorbidities and socsupport deficiencies?

• Key Question 4: What is the relationship between 

incarceration and homelessness among Veterans?
Evidence-based Synthesis Program 

(ESP)

Conceptual Model Conceptual Model

• Framework for conceptualizing associations among r

factors

• Attentive to mediating factors • Is grounded in evidence • Shows gaps in evidence • Identifies poorly understood mechanisms•

Di i ih st nguis

hes “ h d” f “

s

hared”

from 

“Veteran-specifi ”c

” ri ks

k

f
Evidence-based Synthesis Program 

(ESP)
Evidence-based Synthesis Program 

(ESP)

• Veterans appear to be at risk for homeless

much the same reasons as much the same reasons as other US popula

other US popula

• However, their unique experiences as Vete

may mean that they develop these risks thdiff h erent pat

hways.
Evidence-based Synthesis Program 

(ESP)

Key Question 1A: What is the prevalence and Key Question 1A: What is the prevalence and

incidence of homelessness among Veterans?

• Sensitive to definitions and methodologies used• Point

-in

-time (PIT) counts likely: time (PIT) counts likely:

• Over-estimate chronically homeless• Under-estimate the number of individuals and families 

in and out of homelessness
Evidence-based Synthesis Program 

(ESP)

Key Question 1A: What is the prevalence and Key Question 1A: What is the prevalence and

incidence of homelessness among Veterans?

• Veteran Annual Homeless Assessment Report (Vet A

Veteran Annual Homeless Assessment Report (Vet A

estimates

• PIT estimate PIT estimate

• 75,609 on a single night in January 2009• 33 out of every 10,000 Veterans

• Annual estimate (Homeless Management Inform

Systems)

• 136,334 Veterans in emergency shelter or transition

h i 10/2008 housing: 10/2008 – 9/2009
Evidence-based Synthesis Program 

(ESP)

Key Question 1B: How has the prevalence anKey Question 1B: How has the prevalence an

incidence of homelessness among Veterans cover time?

• Estimates generally not comparable due to changes 

methods of reporting and counting

• 1996: 23% of homeless were Veterans (NSHAPC)• 2009: 12% of all homeless; 16% of adults were Vetera

AHAR)
Evidence-based Synthesis Program 

(ESP)

Key Question 1B: How has the prevalence anKey Question 1B: How has the prevalence an

incidence of homelessness among Veterans cover time?

• Changing demographics

• 2009: 24% increase in homeless families seeking servic

2009: 24% increase in homeless families seeking servic

(CHALENG)

• More homeless women Veterans More homeless women Veterans
Evidence-based Synthesis Program 

(ESP)

OEF/OIF H l H M 

Males Females To

OEF/OIF

Home

less: 

How 

Many

Males Females To

OEF/OIFH l 11,307 1,633

1

Homeless ,30 ,633 OEF/OIF served by VHA 549,334 75,344 63by VHAProportion 2.06% 2.17% 2

Source – VA Inpatient and Outpatient Encounter database (October 20
Evidence-based Synthesis Program 

(ESP)

OEF/OIF V H l FY2002 F

5,000

OEF/OIF

Veteran 

Home

less FY2002

– F

3,911

3,0004,000

909

1,463

2,181

1,0002,000

139 152 310 539

0

FY20

FY20

FY20

FY20

FY20

FY20

FY20

FY20

2002

2003

2004

2005

2006

2007

2008

2009

Incidence (new homeless cases)
Evidence-based Synthesis Program 

(ESP)

St d Li it ti St

u

dy Li

mit

ations

• Study samples generally consist of already morbid 

popul i at ons

• Little consistency exists among studies in methodol

instruments used and measurement instruments used, and measurement

• Several studies rely on self-report or on instrument

may not have been validated with homeless populamay not have been validated with homeless popula

• The lack of longitudinal studies limits our understan

cause and effect
Evidence-based Synthesis Program 

(ESP)

Key Question 1C: How prevalent are psychiatKey Question 1C: How prevalent are psychiat

illness, substance abuse, and chronic medicaamong homeless Veterans?

• Wide range of estimates

• Vet AHAR: about 53% have some sort of disability Vet AHAR: about 53% have some sort of disability• Other sources range from:

• 22% - 79% substance abuse• 17%

- 61% psychiatric problems 61% psychiatric problems
Evidence-based Synthesis Program 

(ESP)

K Q ti 2A D hi f th V t Key 

Question 2A: 

Demographics o

f the 

V

e

ter

homeless population 

Percentage Percentage Percentage of Adult US Population 

of Veteran Population 

Percentage of Homeless VeteranPopulation 

Whites 68% 81% 49%Blacks 12% 11% 34%Hispanics 9% 4% 8%American Indian/ Alaska Natives

<1% < 1% >3%
Evidence-based Synthesis Program 

(ESP)

Key Question 2A: Which risk factors are assoKey Question 2A: Which risk factors are asso

with new homelessness or a return to homelamong Veterans? How do these risk factors d

f om non f

rom non

-Vete an pop lations? Vete

ran pop

ulations?

• Childhood risk factors 

• Inadequate care by parents Inadequate care by parents• Experiences in foster care or group placement• Prolonged periods of running away from home. 

• Low or unstable income• Low social support• History of incarceration 
Evidence-based Synthesis Program 

(ESP)

Key Question 2A: Which risk factors are assoKey Question 2A: Which risk factors are asso

with new homelessness or a return to homelamong Veterans? How do these risk factors d

f om non f

rom non

-Vete an pop lations? Vete

ran pop

ulations?

• Compared to non-Veteran homeless, Veterans tend 

• Older• Better educated• Have better early family cohesion• More likely to be or have been married More likely to be or have been married. 
Evidence-based Synthesis Program 

(ESP)

K Q ti 2B H i k f t f h l Key 

Question 2B: 

Have ris

k

fac

tors 

for 

homel

among Veterans changed over time?

•

Mili S l i i i k 

ilitary 

Sexual Trauma an important emerging ris

k

• Increasing risk for family homelessness• Economic and structural factors influence who is at 
Evidence-based Synthesis Program 

(ESP)

F t Di f H l OEF

Diagnosis (ICD-9) Number Perce

(309 81) PTSD 2 124 16 2

Frequen

t Di

a

gnoses 

for 

Home

less OEF

(309.81) PTSD

2,124 16.2

(311) Depressive Disorder NEC (311) 933 7.1(303.90) Alcohol Dependence NEC/NOS 722 5.5(309 9) Adjustment Reaction NOS (309.9) Adjustment Reaction NOS 666 5 1

.

(305.00) Alcohol Abuse - Unspecified 419 3.2(300.00) Anxiety State NOS 359 2.7(309 28) Adjustment Disorder with (309.28) Adjustment Disorder with 293 2 2

Anxiety/Depression

293

2.2

(305.90) Other Drug Abuse - Unspecified 245 1.9(303.93) Alcohol Dependence NEC/NOS – 227 1.7

In remission

(304.20) Cocaine Dependence – Unspec. 223 1.7
Evidence-based Synthesis Program 

(ESP)

K Q ti 3 A th f t ifi t Key 

Question 

3: 

Are there 

fac

tors specific 

to 

service that increase the risk of homelessnesthe increased risk a marker for pre-military 

comorbidities and social support deficiencies• Evidence does not suggest increased “pre-military” • Only two studies have looked at military exposures 

risk factors for homelessness, and findings are mixe

• Study populations were very different (Vietnam-era

predominantly male vs. female from more recent er

• Exposures were defined differently 
Evidence-based Synthesis Program 

(ESP)

K Q ti 3 A th f t ifi t Key 

Question 

3: 

Are there 

fac

tors specific 

to 

service that increase the risk of homelessnesthe increased risk a marker for pre-military 

comorbidities and social support deficiencies• Evidence shows associations between military expo

(combat, injury/trauma) and intermediate outcomthe general population, increase the risk of homele(low income, low social support, incarceration).

• Military risk factors have not been consistently def• Important intermediate outcomes have not been Important intermediate outcomes have not been

consistently defined / have been measured using tvalidated with Veteran homeless populations. 
Evidence-based Synthesis Program 

(ESP)

K Q ti 4 Wh t i th l ti hi b t Key 

Question 

4: Wh

a

t is the relationship 

b

e

tw

incarceration and homelessness among Vete

• Age adj d i i djuste

d incarceration rate 

≈ 1,

2 0 0 000 5

0 per 1

0

,000 

• Incarcerated Veterans as compared with unincarce

Veterans

• Higher rates of drug abuse, treatment for mental illnes

PTSD

• Incarcerated Veterans as compared with incarcerat

Incarcerated Veterans as compared with incarceratVeterans

• More likely to have committed violent offenses• Lower rates of dru

g use

• Comparable rates of alcohol abuse and mental health d
Evidence-based Synthesis Program 

(ESP)

K Q ti 4 Wh t i th l ti hi b t Key 

Question 

4: Wh

a

t is the relationship 

b

e

tw

incarceration and homelessness among Vete

• C bl d h i di i i i i 

Comparable race an

d et

h

nic disparities in incarcera

General 

Population

Federal 

Prison State Prison

White 82% 49% 54%

Black 10% 38% 32%Hispanic 5% 5% 6%
Evidence-based Synthesis Program 

(ESP)

K Q ti 4 Wh t i th l ti hi b t Key 

Question 

4: Wh

a

t is the relationship 

b

e

tw

incarceration and homelessness among Vete

• Very f di f h l d i i few studies o

f

homelessness an

d incarceration 

Veterans

• Homeless and incarcerated have demographic simil

Homeless and incarcerated have demographic simil

• Poor• Uneducated• Over

-representation of minorities representation of minorities

• Incarcerated Veterans face a second instance of re-

stress

• Re-entry post-deployment• Re-entry upon release from incarceration 
Evidence-based Synthesis Program 

(ESP)

K Q ti 4 Wh t i th l ti hi b t Key 

Question 

4: Wh

a

t is the relationship 

b

e

tw

incarceration and homelessness among Vete

• C li l b h l d i 

Cyclical pattern 

between 

homelessness an

d incarce

• Criminalization of homelessness• Ineffective discharge planning• Legal and regulatory restrictions Legal and regulatory restrictions• Full sentencing laws

• Jail diversion 

p g ro

grams

• Few programs and fewer studies• May not be effective at reducing substance abuse or tr

mental illness

• Effective programs can lead to reduced days in jail with

increased risk to public safety 
Evidence-based Synthesis Program 

(ESP)
Evidence-based Synthesis Program 

(ESP)

F t R h P i iti F

u

ture 

Researc

h

P

r

iorities

Overall need for: 

1) Longitudinal studies2

) with OEF/OIF Veterans

3) with data collection on individual and structural ri

factors, and

4) designed to investigate directionality of associatio

(especially for contentious risk factors such as sub

use and mental illness) use and mental illness)
Evidence-based Synthesis Program 

(ESP)

F t R h P i iti ( F

u

ture 

Researc

h

P

r

iorities 

(con

Specific priority areas: 

• Research on the post-deployment period and

1) loss of income

2) l f i l 2) loss o

f social support

3) housing instability4) impact of service injury 

• Qualitative research focused on

1)refinement of measures 

2) post 2) post

-deployment/readjustment experience of diffe

deployment/readjustment experience of diffe

Veteran sub-populations
Evidence-based Synthesis Program 

(ESP)

Summary

• Veterans are homeless for many of the same reason

Veterans; their paths to homelessness likely diffe

r

• Consistent associations of risk factors such as subst

Consistent associations of risk factors such as subst

abuse and mental illness; but causal relationships nfurther exploration

• Changing demographics of the military will call for c

in programs to prevent and address homelessness
Evidence-based Synthesis Program 

(ESP)

Summary

• Important to consider both structural and individua

associated with homelessness as well as their inter

• There are important limitations to the current litera

There are important limitations to the current litera

homelessness
Evidence-based Synthesis Program 

(ESP)

Di i scuss

ion
Evidence-based Synthesis Program 

(ESP)

Quest

ions?

If you have further questions If you have further questions, 

feel free to contact:

H d owar

d Blh a

s

hem, M S. .

503.220.8262 x54487

balshemh@ohsu.edu

The full report and The full report and cyberseminar cyberseminar presentation is available on the E

presentation is available on the E

http://www.hsrd.research.va.gov/publications/esp/
5/23/2011 1:00pm ESP Report: 

Homelessness 

Among Veterans

Spotlight on 

Evidence-based 

Synthesis 

Program

Balshem, Howard

Christensen, Vivian

Kansagara, Devan

Metraux, Stephen

O'Toole, Thomas

Tuepker, Anais

Question submitted

Question: One of the speakers mentioned a potential correlation between increased stability/housing 

with increased substance abuse. Do you foresee research in this area as VA moves toward a housing 

first model? We did not systematically look at the impact of interventions on either homelessness or 

substance abuse following housing as they were outside the scope of our review. However, there have 

been a number of studies looking at the impact of housing on subsequent substance use and comparing 

housing first with treatment first/only or usual care. (O’Connell, Wesley Kasprow, and R. A. Rosenheck 

2008; North et al. 2009; Padgett, Gulcur, and Tsemberis 2006; R. Rosenheck, W. Kasprow, Frisman, et al. 

2003c; Cheng, Lin, Wesley Kasprow, et al. 2007a). Some studies have found no or limited effect of 

housing on substance use(R. Rosenheck, W. Kasprow, L. Frisman, et al. 2003; Padgett et al. 2006; North 

et al. 2009); others have found housing to reduce substance abuse when compared with case 

management only or standard care (A.-L. Cheng, Haiqun Lin, Wesley Kasprow, et al. 2007a; M. J. 

O’Connell, Wesley Kasprow, and R. A. Rosenheck 2008). We agree that such studies are important to 

better help us understand the factors that differentially impact the use of alcohol and drugs subsequent 

to housing interventions.

Question: What do we know about interventions that reduce homelessness in this population? This 

was left out of the review. Was this intentional or is there no literature on successful interventions?

As we noted in our presentation, a review of interventions to prevent or reduce homelessness was 

beyond the scope of the review we were asked to conduct. The VA and the Department of Housing and 

Urban Development have collaborated on a program of supportive housing for Veterans (the HUD-VASH 

program). Some evaluations of that program have found improvements in housing but not clinical 

outcomes (R. Rosenheck, W. Kasprow, L. Frisman, et al. 2003), while others have found improvements in 

both housing and clinical outcomes (Cheng, Lin, Wesley Kasprow, et al. 2007b; M. J. O’Connell, Wesley 

Kasprow, and R. A. Rosenheck 2008). A review of housing interventions for the Campbell Collaboration is 

currently nearing completion and should be available sometime later this year.

Question: Related to the suggestion for longitudinal studies: from your review of the literature, are 

there any good examples of methods for following up with homeless individuals (given the inherent 

difficulty in doing so in this transient population)?

Among others identified in the review cited below, two studies that we are aware of discuss the 

challenges faced by longitudinal studies of homeless populations as well as approaches to 

improving participation and rates of follow-up (Conover et al. 1997; Wright, Allen, and Devine 

2005). We also note the review of the topic by McKenzie and colleagues (1999).

Question: Did risk factors for Veteran homelessness differ between VA patients vs. Veteran 

populations who were not served by VHA?

Much of the research on Veteran homelessness focuses on sample populations that are seeking care 

through the VHA or VA affiliated program such as the Health Care for Homeless Veterans Program. This 

is one of the potential biases of the research on Veteran homelessness, as the findings from these 

studies are not generalizable to the homeless Veteran population as a whole, especially among those 
5/23/2011 1:00pm ESP Report: 

Homelessness 

Among Veterans

Spotlight on 

Evidence-based 

Synthesis 

Program

Balshem, Howard

Christensen, Vivian

Kansagara, Devan

Metraux, Stephen

O'Toole, Thomas

Tuepker, Anais

who are not actively seeking care or those who seek care outside of the VHA. O’Toole (2003) found that 

usual sources of care for the Veteran population in his study were shelter-based clinics and street 

outreach teams while only 41% reported accessing the VA health system for care. We did not identify 

any studies that examined the differences risk factors for homelessness between Veterans who seek 

care from VHA vs. veterans who seek care elsewhere. 
5/23/2011 1:00pm ESP Report: 

Homelessness 

Among Veterans

Spotlight on 

Evidence-based 

Synthesis 

Program

Balshem, Howard

Christensen, Vivian

Kansagara, Devan

Metraux, Stephen

O'Toole, Thomas

Tuepker, Anais

REFERENCES

Cheng, An-Lin, Haiqun Lin, Wesley Kasprow, and Robert A. Rosenheck. 2007a. “Impact of Supported 

Housing on Clinical Outcomes.” The Journal of Nervous and Mental Disease 195(1):83-88. 

Retrieved June 1, 2011.

Cheng, An-Lin, Haiqun Lin, Wesley Kasprow, and Robert A. Rosenheck. 2007b. “Impact of Supported 

Housing on Clinical Outcomes: Analysis of a Randomized Trial Using Multiple Imputation 

Technique.” The Journal of Nervous and Mental Disease 195(1). Retrieved 

(http://journals.lww.com/jonmd/Fulltext/2007/01000/Impact_of_Supported_Housing_on_Clini

cal_Outcomes_.14.aspx).

Conover, S. et al. 1997. “Methods for successful follow-up of elusive urban populations: an ethnographic 

approach with homeless men.” Bulletin of the New York Academy of Medicine 74(1):90.

Michelle McKenzie, Jacqueline Peterson Tulsky, Heather L. Long, Margaret Chesney, and Andrew Moss. 

1999. “Tracking and Follow-Up of Marginalized Populations: A Review.” Journal of Health Care 

for the Poor and Underserved 10(4):409-429. Retrieved May 25, 2011.

North, Carol S., Karin M. Eyrich-Garg, David E. Pollio, and Jagadisha Thirthalli. 2009. “A prospective study 

of substance use and housing stability in a homeless population.” Social Psychiatry and 

Psychiatric Epidemiology 45(11):1055-1062. Retrieved June 1, 2011.

O’Connell, Maria J., Wesley Kasprow, and Robert A. Rosenheck. 2008. “Rates and Risk Factors for 

Homelessness After Successful Housing in a Sample of Formerly Homeless Veterans.” Psychiatr 

Serv 59(3):268-275. Retrieved February 9, 2010.

O’Toole, Thomas P., Alicia Conde-Martel, Jeanette L. Gibbon, Barbara H. Hanusa, and Michael J. Fine. 

2003. “Health Care of Homeless Veterans.” Journal of General Internal Medicine 18(11):929-933. 

Retrieved January 23, 2010.

Padgett, Deborah K., Leyla Gulcur, and Sam Tsemberis. 2006. “Housing First Services for People Who Are 

Homeless With Co-Occurring Serious Mental Illness and Substance Abuse.” Research on Social 

Work Practice 16(1):74 -83.

Rosenheck, R., W. Kasprow, L. Frisman, and W. Liu-Mares. 2003c. “Cost-effectiveness of supported 

housing for homeless persons with mental illness.” Archives of General Psychiatry 60(9):940–

951.

Wright, James D., Tupper Lampton Allen, and Joel A. Devine. 2005. “Tracking non-traditional populations 

in longitudinal studies.” Evaluation and Program Planning 18(3):267-277.