Healthy Homes: Overcrowding

Research question

• What interventions impact overcrowding in housing in the UK?

The Public Health Research (PHR) Programme wishes to fund a number of studies on the topic of UK housing. We recognise that this topic is broad in scope, multifaceted, and involves complex and intersecting issues. Previous research opportunities have been issued on housing-led interventions for homeless people, evictions and homelessness, and the physical quality of UK housing. Applications are still welcome on these topics through the PHR Programme’s Researcher-Led funding stream. This research opportunity focuses on overcrowding.

Housing is an important determinant of health. There is extensive evidence to show that secure, affordable, and decent housing protects individual health and supports communities to be healthy and resilient. As well as the physical and mental health benefits for individuals, families, and communities, healthy homes have the potential to bring wider societal benefits.

Crowded and overcrowded housing is associated with poor health. It can have a negative impact on physical and mental health, causing or exacerbating conditions such as depression and anxiety, aiding the spread of infectious diseases such as Covid and tuberculosis, and increasing the likelihood of accidents, or disturbed sleep patterns. There are also wider social impacts including effects on educational and developmental outcomes.

Overcrowding in the UK is defined in many different ways. Measuring occupation density using the Bedroom Standard, the government’s English Housing Survey 2021/22 found that in England, approximately 732,000 households live in overcrowded conditions. This is 8% of households in the social rented sector, 5% of households in the private rented sector, and 1% of owner occupied households. Scotland, Wales, and Northern Ireland also collect information on overcrowding. Under Part X of the Housing Act 1985, Statutory Overcrowding is a criminal offence and section 327 states that an occupier must not cause or permit overcrowding. Local Authorities have a variety of powers and responsibilities in relation to overcrowded properties.

Overcrowding disproportionately affects people from ethnic minority backgrounds across all housing tenures. English Housing Survey data found that the highest rates of overcrowding were in Bangladeshi (22.5%), Arab (17.1%), black African (16.3%), and Pakistani (13.5%) households. It is also more common amongst people on low incomes and young people. Using data from the English Housing Survey 2021/22, a report by the National Housing Federation states that one in every six children lives in an overcrowded household and further, that a quarter of parents in overcrowded homes regularly sleep in a living room, bathroom, hallway or kitchen because of the lack of space. Overcrowding is not evenly distributed across the UK and is most common in London across all accommodation types.

Solving overcrowding is complex. Various, often interrelated, aspects compound efforts made by local authorities and others to alleviate the housing problems faced by their communities. Poverty, spiralling housing costs, low levels of rental housing stock, levels of housing allowance benefits, and poor quality housing are key factors affecting and worsening the health impacts of overcrowding. In turn, overcrowding can exacerbate poor quality housing. Shelter advises that over one million households are waiting for social homes. Housing shortages can result in many people forced to live in overcrowded accommodation and the literature suggests that it is a driver for homelessness. Reporting in summer 2022, The Commission for Healthy Cities (.PDF) (.PDF) recommended that high priority is given to increasing the supply of affordable and secure housing to combat poverty, inequalities, and poor health.

The Public Health Research (PHR) Programme recognises that some interventions impacting overcrowding are long-term, such as changes in social housing stock availability. However, we are also interested in interventions that have short- and medium-term impacts. Interventions to evaluate might be those which prevent or increase overcrowding itself or those that mitigate the health effects of overcrowding.

The PHR Programme is predominantly interested in the evaluation of interventions operating at a population or sub-population level rather than at an individual level. Interventions should address health inequalities and/or the wider determinants of health. The PHR Programme recognises that interventions are likely to impact different (sub)populations in different ways, and encourages researchers to explore such inequalities of impact in their study design.

Of importance to the PHR Programme is an understanding of inequalities in the impact of interventions on people from particular demographic groups in the UK. Evaluations of interventions seeking to reduce health inequalities experienced by people from ethnic minority backgrounds are of specific interest to the PHR Programme.

Research areas of interest could include but are not limited to:

• The impact of local authority housing policies and neighbourhood planning on overcrowding.
• Interventions to alleviate problems of overcrowding in Houses in Multiple Occupation (HMO) and temporary accommodation.
• Positive and negative impacts of relocation interventions to make best use of available housing stock.
• Evaluations of interventions that impact overcrowding that affect physical features of the home, for example:

1. Interventions to change design and layout, or to extend homes.
2. Interventions which impact access to outside space.
3. Interventions which impact the provision of housing services, repairs and regular maintenance for homes where not all of the space is fully functional.
4. Evaluations of interventions which mitigate the impact of overcrowding during extreme weather events or during emergency response and recovery (e.g., heat and cold, fire and flooding).
5. Interventions external to the home which mitigate the impact of overcrowding on specific populations, for example, access to publicly or communally available facilities or services for children and young people.
6. Research focused on populations who are particularly at risk from the effects of overcrowding, such as people with pre-existing health conditions, disabled people, or people from certain demographic groups, for example, asylum seekers.
7. Effectiveness of interventions that provide advice, support and signposting on, for example, priority banding, housing register applications, transfer applications, mutual exchanges.
8. Local authority strategies focused on working with registered social landlords or private sector landlords, for example interventions which aim to reduce the number of empty properties.
9. The role for decision-makers in the use of timely and relevant data in understanding the scale of local overcrowding.

A range of study designs and outcome measures can be used. Researchers will need to clearly describe and justify their choice of outcomes, and target population group, as well as the rationale for their methodological approach. Researchers will need to specify how outcomes will be measured in the short, medium, and long term.

The PHR Programme typically requires primary outcomes to be direct health outcomes. However, it understands that pathways linking improved housing and health are complex. For this funding opportunity, the Programme will accept the proxy measure of overcrowding as a primary outcome. This outcome measure needs to be appropriately defined and the link to health must be clearly justified. 

Understanding the value of public health interventions - whether the outcomes justify their use of resources - is integral to the PHR Programme, where resources relating to different economic sectors and budgets are potentially relevant. The main outcomes for economic evaluation are expected to include health (including health-related quality of life) and the impact on health inequalities as a minimum, with consideration of broader outcomes welcomed. Different approaches to economic evaluation are encouraged as long as they assess the value and distributive impact of interventions. Applications that do not include an economic component should provide appropriate justification.

Researchers are strongly encouraged to ensure that there is involvement from people with lived experience and other relevant key stakeholders, including decision makers, in the design of the intervention and the evaluation. Researchers can do this by involving them as costed members of the research team. Researchers are encouraged to explain how they will share their findings with local and regional governments, private sector and social housing providers, special interest groups, community audiences, and other relevant stakeholders.

For further information on submitting an application to the PHR Programme, please refer to the Stage 1 guidance notes and PHR supporting information. These can be found by clicking on the relevant commissioned call on the main funding opportunities page. This also includes closing dates and details about how to apply.

In order to apply you will need to carefully review the:

• Stage 1 guidance notes
• PHR supporting information
• Tips for success in applying

Please consult the NIHR Specialist Centre for Public Health (SCPH) about the design of your research as soon as possible. Successful applications generally require a long time (several months) to develop.