Insights article

What is a health impact assessment? Why should you care?

Sebastian Weise
Published: 16/07/2020

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The social distancing measures during the COVID-19 crises demonstrate the importance of activity-friendly neighbourhoods that offer as many walkable features as possible. An active built environment with short distances to essential services and natural spaces supports wellbeing by increasing physical activity by up to 32-59%. The King's Fund estimated that every pound spent on features that promote walking and cycling has a long-term return of £50 and £168, for example, through reductions on the burden on health services. 

PlaceChangers has recently released a product that helps introduce awareness for health outcomes during the design process for new major developments (here's the press release). We held discovery workshops with urban designers from private practices and local authority planners across various parts of England. This article reflects on the role of health impact assessments in new development planning from the standpoint of improved urban design based on our discovery work. 

The link of public health and the built environment is deep and complex, but in recent years a growing body of evidence has been assembled, especially on the value of green spaces. Studies have shown that there is a significant difference in the mental state between those who spend 120 min in green space and those who don’t. Seen over the long-term, easy and regular access to good-quality greenspace has a strong positive impact on individuals’ wellbeing. 

One of the most profound studies of the impact of the built environment on health was conducted by Mitchell and Popham, who studied communities in areas of different levels of deprivation while also considering their respective access to green space locally. The chart below shows the rate of mortality across individuals from different backgrounds came closer where significant greenspace was present. In other words, individuals in deprived neighbourhoods gained in particular from green space; which also suggests a role of greener environments in addressing health inequalities.

Research by Mitchell and Popham

Source: PHE

Health impact assessment

Health Impact Assessments are the main tool for appraising a new development for potential health impacts on the neighbouring population. In the U.K., Wales Health Impact Assessment Support Unit (WHIASU), funded by the Wales Government has been leading in the adoption of Health Impact Assessments in development planning.

At present they are not yet very common in England. Only 30% of councils in one way or another perform or require health impact assessments. In some cases, local authorities require them from the applicant for major applications, which is for example the case in most boroughs of London (e.g. Camden requires a rapid assessment for developments of more than 10 homes or 1000m2; above 99 homes or 9,999m2 floor development area a comprehensive assessment is required - Link) or Essex (more than 50 homes or 1000m2 require a rapid impact assessment - Link).  However, even if not directly implemented by architects or required for submission, aspects of health appraisals can be a part of a baseline analysis for a design and access statement. With the recent attention to the role of our immediate surroundings to personal health, we expect that HIAs will become a more prominent part of the development approval process for new developments.

HIAs provide a framework that captures essential dimensions of urban features thought of being conducive to support health outcomes. There are three primary formats of Health Impact Assessment that can be applied to new development projects (see table below). The format of the health impact assessment depends on the significance of the project, the sensitivity of the site context, and the purpose of the assessment. 

  • Desktop appraisals can be done very quickly by reviewing a few key aspects of the site context and is a general part of any good site analysis. 
  • A ‘rapid’ assessment is often referenced by councils, especially in London, and is a signifier for an assessment that may be submitted with a planning application. This kind of assessment often follows a structured checklist to cross reference evidence.
  • Lastly, a ‘full assessment’ may be a more substantial and very detailed assessment that will be a separate programme of work in itself. This will be a likely requirement for very substantial projects, such as those of national significance, but also substantial residential developments.

Health impacts can also be evaluated at different timing in the life cycle of a design process and approached with a different style: The timing of the impact assessment can be prospective (before project start), concurrent (while the design project unfolds), or after (as a retrospective). In general, a prospective assessment is better than a retrospective as it ensures that the design direction has been influenced by an awareness for health outcomes in the first place.

Type of assessment

Time required



Hours to days

    Limited to no stakeholder engagement
  • Review of readily accessible data
  • Reference to local policies


Days to weeks

  • Steering group and more extensive stakeholder engagement
  • Literature review or study to evidence link between built environment and health
  • Approach is a bit more formalised through checklist templates



  • Extensive stakeholder engagement, e.g. including community needs appraisals (for example with asset based approaches)
  • Dedicated project team and steering group
  • Approach more tailored to the unique requirements surfaced in the early scoping activity 

Rapid health impact assessment for master planned and major developments

Health Impact Assessments are about improving the design and making it sensitive to the site context, especially health impacts. No doubt, there are many other frameworks in existence to support design quality, each with respective focus. While there are overlaps between the criteria in those frameworks, thus far there is no one standard that is particularly focused on health outcomes. Even amongst frameworks for health impacts there are obvious variations. At present, architects/town planners perform site analysis manually using local data and various checklists. 

For example, we reviewed the overlaps and synergies between HIA frameworks used in London and Essex.  The NHS HUDU’s Rapid Health Impact Assessment as used in London is perhaps amongst the better known ones, and it is consistently required by borough councils in London. It has also been used to inspire adaptations, such as the HIA for Essex, which is also used as part of the Livewell developer accreditation scheme developed by Chelmsford Council. 

Essex HIA

London HIA

Major themes

10 dimensions

11 dimensions



51 dimensions

Rapid assessment tools come in the format of a checklist. An overview of dimensions is provided below with a mapping according to the wording in the criteria of the respective section. In both cases the architect used the framework criteria to comment on the likely health impacts. For each criterion, the impact on health outcomes would be described as positive, neutral or negative. There is also a requirement to describe the likely length of that impact and ideally to which population group it applies. 


Essex HIA

London HIA


 Design of homes and neighbourhoods

 Housing design and affordability


 Active environments and active design principle application

 Accessibility and active travel


Access to open, green and blue space

Access to open space and nature


Access to healthcare infrastructure

Access to health and social care services and other social infrastructure


Supporting communities and lifetime neighbourhoods

Air quality, noise and neighbourhood


(picked up in ‘Design of homes and neighbourhoods’)

Crime reduction and community safety


Access to healthier food environments

Access to healthy food


Education, employment and skills

Enter your text here...


(picked up in ‘Design of homes and neighbourhoods’)

Social cohesion and inclusive design


(picked up in ‘environmental sustainability’)

Minimising the use of resources


Environmental sustainability

Climate change

Barriers to using health impact assessments

Generally speaking, the impact assessment requires the cross referencing of substantive evidence both about the population and also the development, the task of completing a HIA can therefore appear daunting, especially for any architect who might not have completed it before. A ‘rapid’ assessment can in practice take a number of days or a couple of weeks to complete. Perhaps most problematic are the sources of funding, as project owners typically are averse to spending substantial funds on baseline assessments, if it is not required by the local authority. 

Practitioners doing the assessment may face further challenges that can make an impact assessment less meaningful for considering health outcomes.

Firstly, health outcome considerations may be critiqued as “wishy washy”, especially if the link between the health outcomes and specific built environment features is not clearly backed by evidence that demonstrates the link. Despite the abundance of evidence and data on public health (the best source for data in England is the PHE’s fingertips data tool — Link), it remains notoriously difficult to make clear links between health outcomes and built features, especially in complex urban environments, where many relationships are at play.

And then there are simple pragmatic issues, for instance, the lack of time for analysis and understanding all the details in the context of the locality. Performing a baseline analysis often relies on conversations with local experts, but a direct involvement of residents is often unfeasible, given the time involved. Health practitioners may not be seen easily to access. Therefore, gathering in-depth insight on a locale’s community assets can be tricky -- “you need to be pointed in the right direction”, which is often by the client.

Clear guidance by local authorities on health outcomes remains rare as there is no commonly agreed position as to the requirements for Health Impact Assessments across the UK; a consistent nationally agreed standard for health impact assessments is lacking. In consequence, understanding in practice remains low; and there is a clear case for data overload, especially when trying to find meaningful evidence that demonstrates specific health deficits in a locality and how to address them. 

Removing barriers to using health impact assessments

We are working towards addressing the above challenges to help architects and developers make wider use of health impact assessments in their work. Lack in time and money presently is a key barrier, which we aim to address. Our actions tap into general suggestions for improvement in practice, for example, including the following suggestions.

    Data and evidence for developers. The data that drives evidence on health outcomes needs to be more contextual, and ideally meaningful. Over time, we need to link evidence of outcomes seen to the changes we make in the built environment. This is a long process and can not be evidenced rapidly. We are working to map the evidence for the outcomes those interventions have on different population groups and their health outcomes. 
    Work towards complementary frameworks. PHE leads this work to mainstream health impact assessments and to push for a few well recognised frameworks to avoid an abundance of checklists or insular approach where everybody creates their own, as consistency is key. 
    Suitable digital tools to support health outcomes. Give local councils, architects, and developers easy to use tools to pro- actively appraise development proposals for health outcomes and consider the needs of the local community given the existing neighbourhood features and public health characteristics. We are working to link built environment and health outcome data so as to create better baseline analysis and ultimately higher quality designs.
    Aiding training and readiness in local councils. This will also help local authorities, who’ll start to look more closely at what outcomes are needed and wanted and how they could be described with greater clarity. For instance, few local authorities presently take health outcomes into consideration in their planning processes. Without clear targets, many councils will find it impossible to measure progress.

As we learn from the pandemic, health outcomes also are supported by good development planning that considered design responses appropriate to the local context. We find it is often through the smaller tweaks and greater collaboration through which architects can unlock opportunities in a master planning project. Seen over the long-term, the more developers can comfortably enable third parties to shape site layouts at earlier design stages, the better for all involved. Opportunities include improved health outcomes for residents both on-site and around, greater quality designs that sell more easily, and are more readily accepted locally. 


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