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Punishing Status and the Punishment Status Quo: Solitary Confinement in
U.S. Immigration Prisons, 2013-2017
Konrad Franco1
Caitlin Patler1
Keramet Reiter2

Franco, K., Patler, C., & Reiter, K. (In Press). Punishing Status and the Punishment Status Quo:
Solitary Confinement in U.S. Immigration Prisons, 2013-2017. Punishment & Society.

SocArXiv Version: 4.0
Last updated: October 29, 2020


Department of Sociology, University of California, Davis.
Department of Criminology, Law and Society, University of California, Irvine.

Corresponding Author: Konrad Franco (
Acknowledgements: This research received generous support from the University of CaliforniaMexico Initiative and the UC Davis Global Migration Center. The authors thank the
Transactional Records Access Clearinghouse and Spencer Woodman with The International
Consortium of Investigative Journalists for sharing data from FOIA requests. The authors also
thank the two anonymous reviewers and editorial team. Ryan Finnigan, Xiaoling Shu, and
participants of the UC Davis Department of Sociology Social Control Research Cluster and the
UC Davis Global Migration Center provided generous feedback along the way.

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This study provides the first systematic, nationally representative analysis of
administrative records of solitary confinement placements in any carceral setting. We examine
patterns in who experiences solitary confinement in Immigration and Customs Enforcement
(ICE) custody, as well as the stated reason for, and length of, their confinement. We reveal
several findings. First, cases involving individuals with mental illnesses are overrepresented,
more likely to occur without infraction, and to last longer, compared to cases involving
individuals without mental illnesses. Second, solitary confinement cases involving immigrants
from Africa and the Caribbean are vastly overrepresented in comparison to the share of these
groups in the overall detained population, and African immigrants are more likely to be confined
for disciplinary reasons, compared to the average. Finally, placement patterns vary significantly
by facility and institution type, with private facilities more likely to solitarily confine people
without infraction, compared to public facilities. This study offers a lens through which to more
precisely theorize the legal boundary-blurring of crimmigration and the relationship between
prison and immigration detention policies, to better understand the practice of solitary
confinement across carceral contexts, and to analyze the relationship between national-level
policy and on-the-ground implementation.
solitary confinement, immigration detention, punishment, discretion

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In 2019, U.S. Immigration and Customs Enforcement (ICE) imprisoned over 52,000
people per day, a daily population 22 times greater than in 1973 (Aleaziz, 2019; Patler and
Golash‐Boza, 2017). ICE subcontracts detention to three to five hundred facilities per year,
including local jails holding a mix of ICE detainees and local prisoners or, in the majority of
cases, for-profit prison corporations operating standalone facilities (Saadi and Tesema, 2019).
Immigration prisons 1 are physically similar to jails and prisons more generally: imposing steeland-concrete structures, with limited access to outdoor areas and natural light, surrounded by
barbed wire fences and armed guards controlling all entrances and exits. These physically
comparable facilities are also experienced similarly by detained people (Longazel et al., 2016).
Still, there are legal distinctions between imprisonment in the criminal and immigration law
contexts that underscore the importance of understanding conditions of confinement. For one,
detained immigrants are not serving sentences: immigration detention is legally considered a
non-punitive administrative process meant to ensure compliance with deportation proceedings.
Detention therefore does not convey the same constitutional protections as in the criminal
context, including the right to a trial to determine whether prolonged detention is justified.2

Immigration detention is most accurately described as imprisonment, and detained people as
prisoners. However, because one of the goals of our study is to build on research on prisons and
jails, and because the two systems are legally distinct (even if they operate identically), we use
“detention” or “immigration prisons” to describe immigration detention and “detained person” to
describe individuals held by ICE. This allows the reader to more easily distinguish between the
immigration and criminal systems and, ultimately, to observe their problematic similarities. In
the future, we urge scholars to move toward using “immigration prisons.”

Immigration law requires mandatory detention for asylum seekers awaiting a credible fear
interview and non-citizens (even lawful permanent residents) who have criminal records. As of
March 2020, 61 percent of detained people had no criminal conviction, and only ten percent had
a serious conviction (TRAC, 2020).

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Detention can therefore extend indefinitely (Transactional Records Access Clearinghouse
(TRAC), 2013). Yet despite the vast and growing use of immigration detention in the United
States, information on the conditions of confinement within ICE facilities is extremely limited.
One of the least understood practices within detention centers is solitary confinement,
leading scholars to describe the practice as a black box within a black box (Patler et al., 2019).
To date, the only national-level examinations of federal data consist of in-depth analyses by
investigative journalists and advocacy organizations, which describe immigrants locked in
windowless cells, alone for 22-23 hours each day, sometimes for weeks or months at a time, and
often with long-term negative effects (Schwellenback et al., 2019; Urbina and Rentz, 2013;
Woodman et al., 2019). Immigrants held in solitary confinement, “suffered hallucinations, fits
of anger, and suicidal impulses. Former [solitarily confined] detainees … experienced
sleeplessness, flashbacks, depression, and memory loss long after release (Woodman et al.,
2019).” Only one existing academic study has examined solitary confinement within the
immigration detention context (Patler et al. 2019). That study revealed similarly troubling
patterns: mentally ill individuals were overrepresented in solitary confinement, the practice
was linked to the onset or worsening of mental illness, and privately-operated facilities were
more likely to use the practice. However, the analysis included only facilities in California.
The present study provides the first national analysis of patterns and practices of solitary
confinement use in immigration detention facilities across the United States. We analyze all
documented cases of solitary confinement lasting 14 days or longer between September 2013
and March 2017 (n=5,327). Solitary confinement for 14 days triggers universal reporting
requirements, pursuant to a 2013 ICE directive requiring facilities to keep records on its use of

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solitary confinement (ICE, 2013).3 The 14-day trigger likely reflects international standards; the
United Nations argues that solitary confinement in excess of 15 days should be banned, and
should never be permitted for individuals with mental illness, because it can amount to cruel,
inhuman, or degrading treatment, or even torture, in violation of international human rights
standards (UN News, 2011; United Nations, 2016). Documenting and analyzing solitary
confinement use in all carceral settings is especially salient, given the potential for serious
human rights violations associated with the practice.
Beyond its practical relevance, our study has empirical and theoretical motivations. First,
no national dataset exists that can examine all cases of solitary confinement in U.S. criminal
prisons; our dataset is therefore the first of its kind in any legal context. We thus provide a
window for better understanding the practice of solitary confinement itself. Second, while
immigration prison conditions are still largely a black box, research on solitary confinement
in the criminal law context has revealed both disproportionate impacts on some groups of
vulnerable individuals and administrative discretion as a central determinant of solitary
confinement practices (e.g., Reiter, 2012, 2016b; Sakoda and Simes, 2020). Given the vast
expansion of crimmigration—the intertwining of the most punitive aspects of criminal and
immigration law as a means of racial social control (Barker, 2017; Bosworth, 2017; Stumpf,
2006)—we hypothesize that these patterns likely also exist in the immigration context. We focus
on operationalizing variables like mental illness status and region of origin, as well as
institutional characteristics like privatization and degree of discretion in imposing solitary
confinement, to test our hypotheses about similar use patterns across criminal and immigration

ICE Directive 11065.1 “Review of the Use of Segregation for ICE Detainees,” is available at:

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contexts and further theorize the legal boundary-blurring of crimmigration. Finally, our data
allow us to examine the theoretical relationship between national-level policy and on-the-ground
implementation. At a time of dizzying federal regulatory change, mining institutional data to
better understand the contagion, and local-level variability, of hidden and discretionary
administrative practices is especially salient.
The Punishment Status Quo: An Epidemic of Solitary Confinement
The exact conditions that constitute solitary confinement, the labels describing it, and the
stated purposes of the practice vary widely across institutions and jurisdictions (Beck, 2015;
Cohen, 2014; Kurki and Morris, 2001; Labrecque, 2019; Lovell et al., 2000; Rubin and Reiter,
2018), making the practice difficult to measure and evaluate. Scholars of solitary confinement in
the criminal context debate everything from its scale (between 80,000 to 250,000 individuals
annually) (Beck, 2015; Lovell and Toch, 2011; Naday et al., 2008), to how harmful it is (Haney,
2018; Morgan et al., 2016), to its purpose (Lovell et al., 2007; Reiter, 2015). Still, as attention to
the practice increases, some academic consensus is coalescing.
Scholars agree that solitary confinement, in both the criminal and immigration context,
has increased in tandem with mass incarceration (Patler et al. 2019; Reiter 2016a; Rubin and
Reiter 2018; Sakoda and Simes 2020; Schwellenback et al. 2019; Woodman et al. 2019). Legal
and social science analyses alike demonstrate that solitary confinement, at least in the criminal
context, is often imposed arbitrarily, by prison officials in perfunctory administrative hearings
(Dolovich, 2012; Reiter, 2016a; Reiter and Coutin, 2017; Resnik, 2020), with disparate use
among racial minorities (Pyrooz and Mitchell, 2019; Reiter, 2012, 2016b; Sakoda and Simes,
2020), and those with pre-existing or new physical and mental health problems (Haney, 2018;

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Kaba et al., 2014; Kupers, 2017; Lovell, 2008; Patler et al., 2019; Reiter et al., 2020; Reiter and
Blair, 2015; Williams et al., 2019).
Indeed, vulnerable populations, including juveniles, pregnant women, and especially
people with mental illness, are likely to be especially susceptible to the negative consequences of
restrictive conditions of solitary confinement (American Civil Liberties Union, 2019; Haney,
2018; Kraner et al., 2016; Reiter, 2016a; Reiter et al., 2020). Yet, solitary confinement is often
the de facto holding place for prisoners who may be unsafe in the general prison population or
those who administrators deem could make other prisoners feel unsafe: transgender people, gang
leaders and dropouts, seriously mentally ill individuals, and most recently, those infected with
COVID-19 (Pyrooz and Mitchell, 2019; Reiter and Blair, 2018; Unlock the Box, 2020). We
assess whether similar patterns emerge in the use of solitary confinement in the immigration
detention context.
Punishing Status: Crimmigration and Mass Immigrant Detention
Just as incarceration increased with more and longer criminal sentences over the past
several decades, so too has immigration law enforcement, including deportations and detention
(Golash-Boza, 2016; King et al., 2012; Patler and Golash‐Boza, 2017). Although immigrants in
detention are awaiting decisions on their immigration court proceedings, not serving criminal
sentences, they can spend months, if not years in prison-like detention facilities; 85,363 people
were jailed for longer than thirty days and 24,897 people for longer than six months in FY 2015
(TRAC, 2013).
“Crimmigration” literature emerged to describe the convergence of immigration and
criminal law’s harshest elements. Crimmigration scholars argue that exclusion, immobilization,
and expulsion are the roles and justifications of both legal systems, ultimately making them co-

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constitutive (Stumpf, 2006, Bosworth, 2017; Bosworth et al., 2018). Further, as Barker has
argued, the merging of “penal power and migration control” undermines “basic principles of
justice,” amplifying indignity, disrespect, and exclusion (2017: 452–3).
A growing body of literature documents the crimmigration convergence and the
individual harms and institutionalized inequity it can cause (Beckett and Evans, 2015; Bosworth
et al., 2018; Chacon, 2012; Eagly, 2010; García Hernández, 2014; Reiter and Coutin, 2017;
Stumpf, 2006). One area of research seeks to document punitive experiences in crimmigration
processes and experiences, including in detention facilities. Scholars argue that despite the legal
differences between criminal incarceration and immigration detention, the physical and
emotional experiences of the systems are parallel (García Hernández, 2017; Longazel et al.,
2016; Patler and Branic, 2017; Reiter and Coutin, 2017). Detained people experience “pains of
imprisonment” (containment, exploitation, coercion, and legal violence) much as prisoners do, in
contexts that are comparably racialized and systemically abusive (Longazel et al., 2016; see also
Brouwer, 2020; Crewe, 2011; Kox et al., 2020). Conditions of confinement in immigrant
detention facilities are troublingly similar to prisons and jails; e.g., lack of legal access, problems
with family visitation, inadequate or inedible food, and subpar or grossly negligent healthcare
(Eagly and Shafer, 2015; Golash-Boza, 2015; Longazel et al., 2016; Patler and Branic, 2017;
Saadi et al., 2020). Of course, detained immigrants may also experience distinctive types of
uncertainty as they await judicial decisions about whether they will be permanently expelled
from the land they call or hope to call home (Bosworth, 2014; Brouwer, 2020; Hasselberg,
Solitary confinement represents one of the most severe and punitive aspects of
crimmigration policy. Indeed, the prison literature shows it is both experienced as punitive and

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often imposed by prison officials for functionally punitive purposes, even when labeled as
administrative or non-punitive (Haney, 2018; Kupers, 2017; Reiter and Coutin, 2017; Sakoda
and Simes, 2020). This punitive and harmful condition of confinement operates similarly in the
immigration detention context but is subject to even less regulation than in prisons. By focusing
on everyday solitary confinement practices in immigration detention, we examine crimmigration
not just as a law making process, but also as a law implementing process—for example, by
demonstrating that local-level law enforcement officials can differentially implement this
punitive form of social control (van der Woude et al., 2014).
Punitive Variability
A robust body of punishment and crimmigration scholarship demonstrates how nominally
uniform policies are implemented differently across different institutions, varying especially with
institutional characteristics, such as whether a given facility is privatized (Lundahl et al., 2009;
Patler et al., 2019; Spivak and Sharp, 2008) and where it is located (Campbell and Schoenfeld,
2013; Gilmore, 2007; Lynch, 2010; Ryo and Peacock, 2018; Schept, 2013; Schoenfeld, 2010).
Administrative discretion (e.g., Reiter, 2016b), local politics (e.g., Barker, 2009; Provine et al.,
2016), and profit motives (e.g., Lundahl et al., 2009) can also influence outcomes, from how
vigorously a jurisdiction polices immigrants (Provine et al., 2016) to the scale and harshness of
conditions of incarceration (Barker, 2009; Lynch, 2010; Reiter, 2016b). These variations in
practice across institutions and jurisdictions contribute to a broader theoretical body of work
challenging the presumption of centralized federal policy in both the criminal (e.g., Campbell
and Schoenfeld, 2013; Lynch, 2010) and immigration (e.g., Patler et al., 2019; Ryo and Peacock,
2018) contexts.

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Patterns in solitary confinement use across different immigration detention facilities and
jurisdictions, all of which are governed by uniform federal standards, allow for an evaluation of
how consistently these uniform standards are applied in practice. To the extent differences in
facility characteristics—like size, geographic location, or privatization—explain variation in
solitary confinement use, we contribute to this body of theory challenging the presumption of
centralized federal punishment policy or practice.
Data and Method
We analyze three administrative datasets from the Department of Homeland Security
(DHS), gathered via Freedom of Information Act (FOIA) requests. The first dataset, acquired by
the International Consortium of Investigative Journalists (ICIJ), contains 5,237 cases of solitary
confinement placements from September 4, 2013 to March 4, 2017, covering cases across 102
facilities under the jurisdiction of 24 ICE Field Office Areas of Responsibility (AORs). The
second dataset, acquired by TRAC, contains individual-level data on all 355,678 people detained
by ICE during FY 2015 (October 1, 2014 to September 30, 2015), the only year for which such
data exist for public use. This allows us to compare solitary confinement cases to overall ICE
populations. The third dataset, also acquired by TRAC, contains information on all ICE detention
facilities from 2009 to 2018, allowing us to control for facility-level characteristics that may
impact solitary confinement use.
Measures and Analytical Approach
Informed by research on solitary confinement in prison and immigration contexts, we
begin by testing whether the use of solitary confinement in immigration prisons
disproportionately impacts some groups and whether it varies significantly across institution
types or facilities. We then model two dependent variables: a continuous variable for length of

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solitary confinement stay (calculated by subtracting the release date from placement date) and a
binary variable to capture the reason for placement into solitary confinement (1 = solitary
confinement without infraction, 0 = solitary confinement with infraction).4 We examine
variations in both dependent variables across individual characteristics, facility type (public or
private), and AOR.
To account for the potential lack of independence between cases and facilities, we use
multi-level mixed effect logistic regression for placement reason and multi-level mixed effect
negative binomial (NB) regression for confinement length. We allow each facility to have their
own intercept and we include AOR fixed effects. Our two-level mixed effect models include two
categories of independent variables: case-level (level-1) characteristics and facility-level (level2) characteristics. Case-level measures include binary variables for gender (1 = male, 0 = female,
as defined by ICE), mental illness (1 = yes, 0 = no), and whether the individual had an attorney
of record (1 = yes, 0 = no), as well as categorical, effect-coded variables for region of origin (1 =
Africa, 2 = Asia, 3 = Caribbean, 4 = Central America, 5 = Europe, 6 = Mexico, 7 = Middle East,

Our binary categorization of solitary confinement placement reasons replicates analyses from
the prison literature (Association of State Correctional Administrators (ASCA) and Liman
Center, 2016; Beck, 2015; Reiter, 2016a), which suggest that placement reason, and especially
placement without infraction, is a source of significant administrative discretion and driver of
solitary confinement patterns of use (Reiter 2012; 2016a).The original dataset contained a 24category “placement reason” variable that details ICE’s primary stated reason for the use of
solitary confinement in each case (see Appendix 1). Solitary confinement with an infraction
(“disciplinary segregation” [ICE, 2013: page 2]), was the most frequently reported rationale.
However, ICE also uses solitary confinement to manage individuals who have not committed a
disciplinary infraction, including in cases where an individual is deemed to constitute a facility
security threat, needs specialized medical attention, seeks or needs protective custody, has a
mental illness, participates in a hunger strike, or is on suicide watch (“administrative
segregation” [ICE, 2013: page 2]). We group these placement reasons into the category of
solitary confinement without infraction (Appendix 1).

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8 = North America, 9 = Oceania, 10 = South America).5 Facility-level measures include a binary
variable for whether a facility is privately operated (1 = private, 0 = public), a continuous
measure of facility population size (calculated by averaging the Average Daily Population (ADP)
across FY 15 to FY 18), and a continuous measure of the percent of the population ICE labels as
“criminal” for each facility (calculated by averaging the “criminal” ADP from FY 15 to FY 18,
Although this is the first nationally comprehensive analysis of solitary confinement, the
data have limitations. First, the data pertain to cases of solitary confinement; ICE redacted all
personally identifying information including individuals’ names, “alien numbers” (a unique
identifier given to each noncitizen), and date of birth. Therefore, some individuals could account
for multiple cases of solitary confinement, but the data do not allow us to determine the extent of
this possibility. Additionally, although the ICE Directive indicates that a detained person’s age,7
physical disability, sexual orientation, gender identity, religion or “special vulnerability” cannot
a priori determine confinement placement, ICE did not provide these variables, so we cannot
evaluate their impact on solitary confinement placement decisions. We also do not have data on
the usage of solitary confinement before the ICE Directive was issued; we therefore cannot
assess change in the frequency or rate of solitary confinement usage before and after the

This categorization follows that of the United States Office of Immigration Statistics; available


ICE classifies National Crime Information Center (NCIC) offense codes into three seriousness
levels. The most serious (level 1) covers “aggravated felonies,” level 2 offenses cover other
felonies, while level 3 offenses are misdemeanors. In these records, the criminal ADP is the
average number of individuals with either a level 1, 2, or 3 offense in custody on any given day.

There have been allegations of solitary confinement use among children in the custody of
immigration authorities (Associated Press, 2018).

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Directive.8 Finally, we observe missingness (ranging from 1.80 to 16.28 percent) on three
demographic variables; because ICE did not provide an explanation of missingness in its data,
we do not know whether the data are missing at random or missing in a systematically biased
fashion. The models we present rely on listwise deletion; sensitivity checks using multiple
imputation by chained equations find similar results.
Descriptive Disproportionalities in Solitary Confinement Use
Table 1 describes the demographic characteristics of detained immigrants subjected to
solitary confinement, compared to the overall population of detained immigrants. Immigrants
with certain characteristics are overrepresented in solitary confinement cases. For example, 95.63
percent of solitary confinement placements involve a male, but only 79.42 percent of all detained
people in the general population are male. Moreover, 20.7 percent of solitary confinement
placements involve individuals with a mental illness, compared to an estimated 15 percent of all
detained people who have a mental illness (Mehta, 2010).9
We also find vast disparities by region of origin. While 24.74 percent of solitary
confinement cases involve individuals from Africa or the Caribbean, people from these regions
collectively represent only 3.64 percent of all detained people. In other words, African and
Caribbean immigrants are overrepresented by a factor of 6.8 in solitary confinement cases when
compared to the larger overall detained population.

The frequency of solitary confinement usage increased slightly each FY after the 2013 ICE
Directive made data available: there were 1,380 placements in FY 2014, 1,488 in FY 2015, and
1,702 in FY 2016.

The rate of undiagnosed mental illness is unknown in immigration detention centers, prisons,
and jails since many of these facilities lack appropriate mental health screening assessments
upon booking.

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==================== Table 1 About Here ====================

Length of solitary confinement placement varied widely, across both individual
characteristics and placement reason; Figure 1 shows an overall mean of 43 days and a median of
27 days. However, 171 cases (3 percent) lasted more than 6 months, including 22 cases lasting
over a year and one lasting over two years. These 23 longest-lasting cases had distinctive
characteristics: 60 percent of these cases involved individuals with a mental illness; 80 percent
were “administrative,” with no underlying disciplinary infraction; and 90 percent were in
privately-operated facilities.

==================== Figure 1 About Here ====================

Solitary confinement with an infraction was ICE’s most common placement justification:
53 percent of all cases followed an infraction; 47 percent were initiated without an infraction.
However, Figure 2 reveals that ICE’s stated placement reasons varied widely across detention
facilities; ICE facilities seemingly interpret and apply the same regulations differently.

==================== Figure 2 About Here ====================

Solitary confinement practices also differ across institution type and size. Some facilities
have no reported cases of solitary confinement at all. However, facilities where solitary
confinement was used at least once are larger, in terms of their ADP, than the average facility
(799 people detained per day vs. 317; Table 1). In addition, facilities that use solitary

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confinement also have a higher share of their population characterized by ICE as “criminal,”
compared to the average facility (60.69 percent of the facility population vs. 44.62 percent).
Analytical Disproportionalities in Solitary Confinement Use
Our multilevel regression models reveal that variations in placement reason and length
are significantly related to case-and facility-level characteristics and AOR. In Table 2, we
display results from two nested mixed effect logit regression models predicting placement reason
(with a disciplinary infraction vs. without). The first model controls for demographic and facility
variables; the second adds an interaction term between the binary mental illness and private
facility variables. In Figure 3, we visualize these regression results by plotting the average
marginal effects (AMEs) of the independent variables on the predicted probability of solitary
confinement placement without a disciplinary infraction. In Table 3, we show results from two
nested mixed effect negative binomial regression models predicting the length of solitary
confinement stay. The first model controls for placement reason along with demographic and
facility variables; the second adds an interaction term between the binary placement reason and
private facility variables. In Figure 4, we plot the average marginal effect (AMEs) of predictors
on the predicted number of days spent in solitary confinement. All models control for gender,
attorney representation, physical health, mental illness, facility operator type, facility size
(average daily population), and average “criminal” ADP. All models also control for AOR and
allow for each facility to have their own intercept.

==================== Table 2 About Here ====================
==================== Table 3 About Here ====================
==================== Figure 3 About Here ====================

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==================== Figure 4 About Here ====================

We organize our interpretation of these models around key theoretically- and policy-relevant
predictor variables.

Mental Illness
ICE is more likely to justify solitary confinement cases involving individuals with mental
illness as confinement without disciplinary infraction, compared to individuals without mental
illness (predicted probability of confinement without infraction is 63 vs. 43 percent). In addition,
cases involving individuals with a mental illness last approximately 15 days longer than cases
involving individuals without mental illness (56 vs. 41 days).
The placement of individuals with a mental illness in solitary confinement without
infraction and for longer periods of time could suggest that solitary confinement is used in times
of “medical crises.” However, cases ICE defines as involving individuals with a “serious medical
issue” last about 18 days less, on average, than cases involving individuals without a serious
medical issue. These results strongly suggest that solitary confinement is, rather, an ongoing
strategy for managing but not treating mental illness, amplifying prior research focused on
immigration detention in California (Patler et al., 2019), and in prisons more generally (Reiter
and Blair 2015).
Region of Origin
Region of origin is significantly correlated with both placement reason and length. ICE is
more likely to justify solitary confinement cases involving people from Africa as due to an
infraction (i.e. for disciplinary reasons): the predicted probability of solitary confinement without
infraction is 33 percent for individuals from Africa, compared to 40 percent for the entire

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sample. Importantly, no individual African country statistically drives this finding, suggesting
the possibility of racialized differential treatment. In terms of solitary confinement length, cases
involving immigrants from the Middle East last approximately 5 days longer, compared to the
grand mean. Cases involving individuals from Mexico last about 2.5 days less, compared to the
grand mean. This may be because there are fewer legal options to prevent deportation from
Private and Public Facilities
Facility type is significantly correlated with solitary confinement placement reason and
length of confinement. Privately operated facilities are significantly more likely to place
individuals in solitary confinement without an infraction (predicted probability of 53 percent),
compared to publicly run detention facilities like local jails (predicted probability of 35 percent).
Although we find no statistically significant average differences in the predicted length of
solitary confinement between private and public facilities, we do find a significant interaction
between the facility type and placement reason. As demonstrated in Model 2 of Table 3, cases
involving people who are solitarily confined without infraction last an average of 4 days longer if
they take place in a private facility, compared to a public facility. This exaggerates an already
significant difference between the average length of solitary confinement for cases with and
without infraction (30 versus 60 days, respectively).
Detention Facilities and ICE Field Office Areas of Responsibility (AORs)
Placement reasons and lengths of stay also vary at the facility- and AOR-level (see
Appendix 2), suggesting that solitary confinement, though federally regulated, is interpreted
differently by different field offices. Although scholars have documented similar variation in
solitary confinement across U.S. state prison systems (Association of State Correctional

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Administrators (ASCA) and Liman Center, 2016), each state jurisdiction has distinct rules
governing solitary confinement placements. That is not the case with ICE AORs, which are all
governed by identical federal regulations, and therefore should not exhibit different practices.
While it is beyond the scope of our data to explain the observed variation across AORs, literature
from the prison context suggests the possibility that economic (e.g., El Sayed et al., 2020) and
political (e.g., Campbell, 2011) factors could contribute to differences across AORs.
Solitary confinement signifies deprivations of human contact, sensory stimulation, and
freedom of movement, which increase the risks of severe mental and physical deterioration. For
these reasons, the United Nations has declared that more than 15 days in such conditions can
constitute torture, in violation of international law (UN News, 2011). Our unique national data
set, encompassing the known universe of solitary confinement placements in immigration
detention centers between 2013 and 2017, allows us to quantify the scale and analyze the
disparate impact of these solitary confinement experiences. We provide the first systematic,
national-level analysis of administrative records of solitary confinement placements—not only in
immigration detention, but in any carceral setting. Moreover, multivariable analyses of nationallevel administrative data have been missing until now. Our analyses allow us to more precisely
theorize the integration not just of criminal and immigration law (“crimmigration”), but also the
integration of prison and detention policies governing conditions of confinement and day-to-day
treatment. By presenting analyses from the immigration detention context, we can compare our
findings with what is already known about solitary confinement use in prisons and jails. Further,
we can theorize how these practices might be legally, administratively, and practically related,
working together to exclude individuals from civil rights and social benefits.

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We find that solitary confinement use in U.S. immigration detention facilities replicates
many of the patterns of solitary confinement use in U.S. prisons. First, solitary confinement in
immigration detention punishes status, not only in the general sense of affecting people who
have the status of immigrant, but in the more individualized sense of disproportionately affecting
people with certain additional status characteristics. Immigrants from Africa and the
Caribbean—likely to be racialized minorities—are overrepresented in solitary confinement cases
by 680 percent, compared to their share of the detained population. Further, immigrants from
Africa are much more likely to experience solitary confinement for disciplinary reasons than the
average detained person. This reflects patterns of disproportionate solitary confinement of racial
minorities for disciplinary reasons in the prison literature (ASCA and Liman Center, 2016;
Reiter, 2012; Schlanger, 2013; Tasca and Turanovic, 2018). Inasmuch as region of origin may be
a proxy for race, our findings provide additional evidence that race and systems of punishment
are mutually constituted (Cleve and Mayes, 2015), with overly punitive outcomes for Black
Detained immigrants who are mentally ill are more likely to be placed in solitary
confinement for longer periods than people without mental illness (see also Patler et al., 2019),
again reflecting patterns documented in the prison context (Clark 2018; American Civil Liberties
Union 2019; Kaba et al. 2014; Reiter et al. 2020; Reiter and Blair 2015). This is particularly
troubling since solitary confinement is known to both initiate and exacerbate serious mental
illness (Haney, 2018; Reiter and Blair, 2015; UN News, 2011).
Solitary confinement practices also vary across detention institutions and jurisdictions,
just as they vary across prison institutions and jurisdictions (Beck, 2015; Cohen, 2014; Kurki and
Morris, 2001; Labrecque, 2019; Lovell et al., 2000; Rubin and Reiter, 2018). In particular,

Page 19

privately-operated detention facilities are more likely to use solitary confinement for
administrative, non-disciplinary reasons, compared to public facilities (e.g., local jails). This
suggests that private facilities interpret the same federal policies differently from public
facilities, segregating detained people for more vague and variable reasons. Such rogue patterns
of behavior by for-profit detention contractors have motivated ongoing litigation and legislative
efforts to ensure compliance with basic contractual federal standards, such as California
Assembly Bill 3228.10
Another central theme of our findings is that administrative discretion governs who is
placed in solitary confinement in immigration detention, why, and for how long—just as in the
prison context (Dolovich, 2012; Reiter, 2016a; Shapiro, 2019). We find that placement decisions
are, at best, inconsistent, and, at worst, arbitrary and, likely, dangerous. In the prison context,
scholars have argued that solitary confinement is a magnifying lens for understanding the
problems of incarceration more broadly: from the challenges of handling mentally ill prisoners to
the broad discretion correctional staff wield over the day-to-day lives of prisoners (Reiter, 2016b;
Resnik, 2020). Similarly, solitary confinement in immigration detention is a magnifying lens for
understanding both which populations are most vulnerable to detention and how much power
ICE officials wield over their lives, a haunting example of crimmigration law in action (van der
Woude et al., 2014). The patterns we document strongly suggest that solitary confinement use
has been thoroughly integrated into the administrative detention setting of ICE, becoming part of
the broader punishment status quo documented in the prison context (Beck, 2015; Cohen, 2014;
Kurki and Morris, 2001; Labrecque, 2019; Lovell et al., 2000; Rubin and Reiter, 2018).


Page 20

Our study represents a crucial step towards better understanding the use of solitary
confinement in immigrant detention and in carceral settings, but this topic demands more
scholarly attention. More work must address (a) the experiences of marginalized groups
(including Black migrants, people with mental illnesses, people who speak languages other than
English and Spanish, and LGBT migrants) in solitary confinement, (b) the role of detention
facility personnel in interpreting regulations and imposing solitary confinement, and (c) the
interrelated health and legal consequences of being solitarily confined in immigration detention.
In light of both the growing use of solitary confinement in the United States and
increasing documentation of its negative health consequences, scholars increasingly call for a
public health perspective on this deep end of mass incarceration (Ahalt et al., 2019, 2020; Ahalt
and Williams, 2016; Reiter et al., 2020). Such a perspective theorizes the experience of
incarceration in extreme conditions as a disease requiring systemic mitigation and treatment,
rather than punishment at the individual level, before it spreads like a contagion. To extend the
health analogy, our data suggest that solitary confinement is institutionally contagious as well—
spreading from the punitive setting of prisons to the administrative setting of immigration
detention. The “contagion” analogy is even more pressing and poignant in 2020, with the world
facing a global pandemic and imprisoned people across the U.S. facing solitary confinement in
an effort to curb the spread of COVID-19 (Cloud et al., 2020), with sometimes deadly
consequences (Plevin, 2020).
While a major national and international movement is curbing both the frequency and
duration of solitary confinement placements in prisons (at least prior to the COVID-19
pandemic) (ASCA and Liman Center, 2016; Reiter and Blair, 2018), our data suggest that no

Page 21

such curbs exist on solitary confinement use in immigration detention. Although the September
2013 ICE directive aimed to encourage “careful consideration of alternatives” to solitary
confinement placement and to protect people with “special vulnerabilit[ies]” (ICE, 2013), we
find that solitary confinement use is frequent, and vulnerable populations are at more risk of
solitary confinement placements than non-vulnerable populations. Moreover, in December of
2019, ICE revised the National Detention Standards that regulate conditions of confinement in
immigration detention. The new provisions remove procedural protections preceding solitary
confinement placement and permit the use of administrative solitary confinement for a broader
range of reasons (Cho, 2020). Given the many disparate impacts of solitary confinement on
specific vulnerable groups, and its inconsistent, discretionary application across facilities and
regions, the 2019 Standards revision are likely to exacerbate the inequities and inconsistencies
we document, even absent the new implications of a pandemic. These inconsistencies and
inequities, in turn, run the risk of violating established international human rights protections.

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Biographical Notes
Konrad Franco is a Sociology PhD student at the University of California, Davis. His research
interests broadly pertain to the sociology of law and punishment along with quantitative
methods. He studies jails, prisons, and immigration detention centers using administrative data.
Caitlin Patler is an Assistant Professor of Sociology at the University of California, Davis, and
an Executive Committee Member of the UC Davis Global Migration Center. Her research
addresses the origins and reproduction of inequality in the U.S. through an examination of laws,

Page 28

legal statuses, and law enforcement institutions as drivers of socioeconomic and health
Keramet Reiter is an Associate Professor in the Department of Criminology, Law & Society
and at the School of Law at the University of California, Irvine. She is the author of 23/7 (Yale
University Press, 2016) and Mass Incarceration (Oxford University Press, 2017), and her
research focuses on prison conditions, laws, and policies.

Page 29

Table 1. Summary Statistics for Key Variables with Comparison between the
General Detained Population and Solitary Confinement Population
Solitary Population
General Detained Population
Frequency Percentage/Mean Frequency Percentage/Mean
Male (1 = yes)
Attorney of Record (1 = yes)
Serious Medical Issue (1 = yes)
Mental Illness (1 = yes)
Region of Origin (1 = yes):
Central America
Middle East
North America
South America
Average Facility Daily Population (ADP)
Share of Facility ADP Criminal
Private Facility Operator
Solitary population data come from the ICIJ.
General detention population data come from TRAC, except where indicated.
Data about the full general detention population come from FY 2015, except where indicated.
“—” denotes no available data.
ADP data averaged from FY 2015 to FY 2018.
ICE classifies National Crime Information Center (NCIC) offense codes into three seriousness levels; the
most serious (level 1) covers “aggravated felonies,” level 2 offenses cover other felonies, while level 3
offenses are misdemeanors. The share of facility ADP that is criminal is the percent of the ADP with either a
level 1, 2, or 3 offense.
Eagly and Shafer (2015) b Mehta (2010)

Page 30

Table 2. Mixed Effect 2-Level Logit Regression Predicting Solitary Confinement Without a Disciplinary Infraction
Yes-Attorney of Record
Yes-Medical Issues
Yes-Mental Illness
Region of Origin (Ref: sample grand mean):
Central America
Middle East
South America
Average Facility ADP FY15-FY18
Share of Facility ADP Criminal FY15-FY18
Private Facility
Yes-Mental Illness x Private Facility
SD of Random Facility Intercepts
AOR Fixed Effects
5294.992 5303.133
5033.535 5035.299
-2475.767 -2475.649
Log odds coefficients.
Standard errors in parentheses.
p < 0.10, * p < 0.05, ** p < 0.01

Page 31

Table 3. Mixed Effect 2-Level Negative Binomial Regression Predicting Number of Days in Solitary Confinement
Confinement without Infraction
Yes-Attorney of Record
Yes-Medical Issues
Yes-Mental Illness
Region of Origin (Ref: sample grand mean):
Central America
Middle East
South America
Average Facility ADP FY15-FY18
Share of Facility ADP Criminal FY15-FY18
Confinement without Infraction x Private Facility
SD of Random Facility Intercepts
AOR Fixed Effects
39767.846 39771.154
39493.634 39490.566
-19703.817 -19701.283
Coefficients represent the difference between the log of expected counts.
Standard errors in parentheses.
p < 0.10, * p < 0.05, ** p < 0.01

Page 32

Figure 1. Distribution of Time Spent in Solitary Confinement

14-29 days

30-59 days

60-89 days

90-119 days

120-149 da ys

150-179 da ys

180+ days




Number of Cases




Page 33

Figure 2. Distribution of Select Placement Reasons Across 25 of the Largest Detention Facilities
Adelanto (CA)
Baker County (FL)
CCA Florence (AZ)
Denver (CO)
Eloy Federal (AZ)
Etowah County (AL)
Farmville (VA)
Henderson (NV)
Houston (TX)
Hudson County (NJ)
Imperial (CA)
Jena/Lasalle (LA)
Krome North (FL)
Northwest (WA)
Otay Mesa (CA)
Pike County (PA)
Pine Prairie (LA)
Rio Cosumnes (CA)
Santa Ana (CA)
Sherburne County (MN)
South Louisiana (LA)
South Texas (TX)
Stewart (GA)
York County (PA)
Yuba County (CA)








Solitary Confinement with Infraction
Solitary Confinement without Infraction


Proportion of all Solitary Confinement Placements
Note: Figure limited to 25 facilities with highest average daily populations (ADP)

Page 34

Figure 3. Average Marginal Effects (AMEs) of Independent Variables on the Predicted Probability of Solitary
Confinement without Disciplinary Infraction


Yes-Attorney of Record
Yes-Medical Issues
Yes-Mental Illness
Central America
Middle East
Average Facility ADP FY15-FY18
Share of Facility ADP Criminal FY15-FY18

. . . . . . . . . . ..... :· ..... ·:· . . . . . . .... ...... .... .



Page 35










Note: 95% confidence intervals shown. North America and Oceania omitted due to small n.


. . · 1'



...... .................... ......


!• • • '•
' ' ''' ' ; '''' :''''' ·.·''••• :••••• ' •••• !••••• !•••••••••••• •i•• • • • • ,• • •

Average Marginal Effect on Predicted Probability of
Solitary Confinement without a Disciplinary Infraction

-:---~---8 -·-·t---r--t-TTT _____ •

Figure 4. Average Marginal Effects (AMEs) of Independent Variables on the Predicted Number of Days Spent in
Solitary Confinement


Solitary Confinement without Infraction


... I




Yes-Attorney of Record


Yes-Medical Issues

. " .~ ' .

Yes-Mental Illness

"· i ·















·••••·.,.....+--'I •·

Central America


Middle East

Average Facility ADP FY15-FY18

···· · Ci>· ··


Share of Facility ADP Criminal FY15-FY18

·· 8I ··





Average Marginal Effect on
Predicted Number of Days in Solitary Confinement



Note: 95% confidence intervals shown. North America and Oceania omitted due to small n.

Page 36

Appendix 1. Coding Scheme for Placement Reason Variable

ICE Provided Reason
Pending Investigation of Disciplinary Violation
Facility Security Threat: Due to Seriousness of Criminal Conviction
Facility Security Threat: Gang Member Status (Not Protective Custody)
Facility Security Threat: Other
Facility Security Threat: Violent or Disruptive Behavior
Hunger Strike
Medical: Detox/Withdrawal Observation
Medical: Disabled or Infirm
Medical: Observation
Medical: Other
Medical: Other Infectious Disease
Medical: Segregation Unit
Medical: Tuberculosis
Mental Illness
Mental Illness: Observation
Protective Custody: Criminal Offense (b)(7)(e)
Protective Custody: Gang Status (Protective Custody Only)
Protective Custody: Lesbian, Gay, Bisexual, Transgender (LGBT)
Protective Custody: Other Detainee Safety
Protective Custody: Special Vulnerability Other
Protective Custody: Victim of Sexual Assault
Suicide Risk Placement




Page 37

Appendix 2. Average Marginal Effects (AMEs) of Individual ICE AORs on the Predicted Probability of Solitary
Confinement without Disciplinary Infraction and the Predicted Number of Days in Solitary Confinement
BAL (Baltimore)

BAL (Baltimore)



BOS (Boston)

BOS (Boston)


BUF (Buffalo)

BUF (Buffalo)


CHI (Chicago)


DAL (Dallas)

DAL (Dallas)



DEN (Denver)

DEN (Denver)


DET (Detroit)

DET (Detroit)



ELP (El Paso)
HOU (Houston)

ELP (El Paso)
HOU (Houston)

-: -----e---;.

LOS (Los Angeles)


MIA (Miami)



PHI (Philadelphia)
PHO (Phoenix)

--9- j ·

SEA (Seattle)

SEA (Seattle)


. • •• • •• • •• I•

SFR (San Francisco)


SLC (Salt Lake City)



SND (San Diego)

--- e - - ,-

SPM (Saint Paul)



WAS (Washington)


..... ..

SFR (San Francisco)

·: ----e--+-

SNA (San Antonio)


NYC (New York City)


PHO (Phoenix)


·: ..

.- ,.

NOL (New Orleans)


PHI (Philadelphia)


NEW (Newark)


NYC (New York City)


MIA (Miami)


NOL (New Orleans)


LOS (Los Angeles)


NEW (Newark)


CHI (Chicago)


Average Marginal Effect on Predicted Probability of
Solitary Confinement without a Disciplinary Infraction


SLC (Salt Lake City)
SNA (San Antonio)
SND (San Diego)


SPM (Saint Paul)


WAS (Washington)


Average Marginal Effect on
Predicted Number of Days in Solitary Confinement

Note: 95% confidence intervals shown. Deviation effect coding. Atlanta AOR excluded.

Page 38