Hidden homelessness: international evidence review

This report "Exploring Ways of Identifying and Counting Hidden Homeless Populations" presents an overview of the methods used internationally to identify or count people experiencing hidden forms of homelessness and the populations that may be likely to experience it. The report also considers the Scottish context and suggests areas where further research may be useful.

2. The evidence base

2.1 Methodology

This work is intended as a scoping review and is not intended to be exhaustive. While every attempt was made to explore the literature in a robust way, this work does not constitute a systematic review and, therefore, it is possible that some relevant sources may not be included.

Studies are reported as they were described in the literature at the time of their production, and data are gathered from multiple places and multiple time periods. As such, this paper is not intended to provide a comprehensive analysis of policy actions or positions in Scotland or elsewhere.

The primary aim of this evidence review is to identify key studies, assess their quality, and synthesise the findings to provide a clearer understanding of the international evidence base on methodologies to count/identify those experiencing concealed forms of homelessness. It has been guided by three main objectives:

1. Explore which methodologies have proven to be more effective at identifying people experiencing housing insecurity and/or hidden homelessness, their strengths and limitations

2. Explore which population groups experiencing housing insecurity and/or homelessness are described within the literature as being undercounted or missed by homeless counts

3. Briefly reflect on advantages and limitations of these approaches in relation to the Scottish context

The definition of hidden homelessness used in this report has been kept as comprehensive as possible to be able to capture a broad evidence base across countries which may have differing approaches to this matter.

2.1.1 Literature search

The literature search was conducted by The Scottish Government library which included databases such as: Idox, KandE, Knowledge Network, Policy Commons, ProQuest, Social Care Online and Google Custom Search. It was supplemented by the use of supplementary additional searches carried out by Scottish Government social researchers using online tools such as Google Scholar and broad search engine searches. The search terms were drawn from an initial scoping of known hidden homelessness literature and included: 'hidden homelessness', 'statistics', 'enumeration', 'count', 'sofa surfing', 'doubling-up', 'overcrowding', 'unsheltered', 'rough sleeping', 'housing insecurity', 'squatting', 'survival sex' among others. These terms were drawn from an initial scoping of key terms from relevant articles.

Included in this this review are:

  • studies published between 2000 and 2023
  • studies published in the English language
  • publications that present/discuss research on methods to count/identify homeless and hidden homeless populations
  • publications that present research conducted with a specific subgroup of the populations often missed in homelessness counts (ethnic minorities, refugees, LGBTI+, young people, women, etc.)

Excluded from this review are:

  • studies where the methodology used was unclear, inconsistent with the results produced and/or lacked a thorough explanation
  • opinion pieces

Once the literature for inclusion from the library search was identified and classified, the references mentioned in the identified publications were used to find other relevant publications that met the inclusion criteria and were not found in the initial database searches. This is also known as 'snowballing' and helped broaden the search.

The selected publications consist of peer-reviewed and grey literature that discuss ways of identifying and counting hidden forms of homelessness and the population groups they focus on. This includes mostly quantitative and mixed-methods research except for some qualitative pieces focussed on informing better ways to access and count forms of hidden homelessness. Literature was purposefully included if it had clear methods sections and reflected on limitations when possible.

The delineation between homelessness in the broader sense, and hidden homelessness more specifically is blurry and may differ from country to country. This needs to be considered when comparing data from multiple countries, bearing in mind that those who experience hidden forms of homelessness, and the meaning attached to these forms, is dependent on the specific context in which they exist.

2.1.3 Limitations

Although a robust approach has been taken to mitigate any shortcomings within the conduct of this review, it is not intended to be an exhaustive or traditionally 'systematic review' of evidence and, as such, there are a number of limitations. Due to the nature of this type of review, it is possible some literature may have been missed.

For pragmatic reasons, only materials published in English were included, however, we are aware that when dealing with an international evidence base, this narrows the reach of our search.

Some reviewed evidence came from studies/publications with a wider focus on homelessness and not specifically hidden homelessness. This has been clearly reflected upon when discussing those materials to ensure caution is taken when applying their findings to the hidden homeless population.

2.2 Glossary

In this section we have included a glossary of terms often used both in the literature reviewed and when discussing homelessness. These definitions are meant to provide clarity and consistency on the terms used across multiple countries and pieces of literature and are not exclusive to Scotland.

Asylum seeker: The UNHCR defines an asylum-seeker as an individual who has left their country of origin in order to seek asylum in another country, someone whose request for sanctuary has yet to be processed. (Source: Asylum-seekers | UNHCR and Asylum in the - UNHCR United Kingdom)

Domestic abuse: this includes violence, harassment, threatening conduct, and any other conduct giving rise, or likely to give rise, to physical or mental injury, fear, alarm or distress. Conduct includes speech and/or presence in a specified place or area. This includes therefore, persons experiencing non-violent domestic abuse, where abuse is interpreted as extending beyond physical violence to included threatening behaviour, violence or abuse (psychological, physical, sexual, financial or emotional). This can also include coercive control. (Source: Domestic abuse, housing and homelessness in Scotland: An evidence review)

Doubled-up: when more than one household lives in the same dwelling because they lack the means to have their own. This can be also sometimes referred to as the presence of a 'concealed household' within other.

Enumeration: is the action of establishing the number of something. In this report this term is mostly used in reference to the number of people experiencing hidden homelessness.

Minority ethnic: This report uses the term 'minority ethnic' to refer to those individuals belonging to ethnic groups that are in a minority in the other populations. This term includes non-visible White minority groups such as Polish or Irish Traveller. It is preferable for the word 'minority' in 'minority ethnic' to come first to acknowledge that everyone has an ethnicity and that minority ethnic groups in the UK are not necessarily a minority in populations elsewhere around the globe.

Relatively popular terms such as 'BAME' (Black, Asian and minority ethnic) and 'BME' (Black and minority ethnic) are also avoided due to their implicit homogenisation of different ethnicities into a singular, unified identity. Where these terms appear in this text it is to reflect the wording of the original research.

Housing insecurity: the state of not having stable or adequate living arrangements, especially due to risk of eviction or because one lives in unsafe or uncomfortable conditions.

LGBTI: this term stands for lesbian, gay, bisexual, transgender and intersex. Other acronyms were used in some of the research cited and will be used only when referring to it.

Local connection: in the Scottish context, this refers to a homelessness applicant's connection formed on the basis of residence regarding employment, family associations or any special circumstance (Source: Section 1: Background - Local connection and intentionality provisions in homelessness legislation: consultation - gov.scot (www.gov.scot)).

Overcrowding: is used to refer to the living circumstances where the number of people living in the same dwelling is above the desired limits for wellbeing and privacy. The Housing (Scotland) Act 1987 defines overcrowding as the situation when the number of persons sleeping in a house contravenes the room or place standard (these are based on the number of bedrooms and baths shared).

England and Wales have two main definitions of overcrowding. One, known as 'the room standard' that focuses on the number of inhabitants in a dwelling of a certain size. The other, known as the 'space standard' that focuses on the number of bedrooms available in a dwelling and their square footage (Addison, Batt, & Stock, 2022; The Scottish Government, 2021).

Refugee: The definition of a refugee according to the 1951 Refugee Convention is someone who: 'Owing to a well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group, or political opinion, is outside the country of his nationality, and is unable to or, owing to such fear, is unwilling to avail himself of the protection of that country.' Refugee Status Determination is the process in which either the host government or UNHCR determine whether an asylum-seeker meets the definition of a refugee. (source: Asylum in the - UNHCR United Kingdom)

Rough sleeping: refers to people who are bedded down outside, in the open air (such as on the streets, or in doorways, parks or bus shelters) or sleeping in a building or other place not designed for habitation (such as barns, sheds, car parks, cars, derelict boats, stations etc.).

Sofa surfing: refers to people who are living with others involuntarily and/or do not have the right or option to remain indefinitely. Also referred to in some evidence as 'couch-surfing' or 'staying with friends and family'.

Squatting: legally in the UK, this is when someone deliberately enters property without permission and lives there or intends to live there. Squatting is sometimes a response to homelessness. People experiencing homelessness who squat occupy empty, usually disused or abandoned property, not other people's homes. (Sources: Squatting and the law: Overview - GOV.UK (www.gov.uk) and squatting_a_homelessness_issue_2011.pdf (crisis.org.uk))

Survival sex: is the exchange of sex for material support, in this case, a place to spend the night when homeless.

Temporary accommodation: is the housing provided by local authorities to people experiencing homelessness or housing insecurity (depending on the country). This can include different types of dwellings in social sector accommodation, hostels, bed and breakfasts, community housing or refuges among others.


Email: socialresearch@gov.scot

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