Health Impact Assessment: screening to full assessment

A Health Impact Assessment is not required by national legislation for planning applications in England. It is required by local policy, and that is why the first question on any scheme is which council you are in and what its validation list says. Where an HIA is required, the work usually begins with a screening stage that either closes the matter or determines whether a rapid or a full assessment follows. Getting the screening right saves a great deal of unnecessary work.

Which councils require an HIA and at what scale

The requirement comes from three places. Some local plans carry a health and wellbeing policy that asks for an assessment above a stated scale. Some councils put an HIA on their local validation list, which makes it a document without which the application will not be validated. In London, the London Plan expects health impact assessment for larger schemes, and boroughs apply it through their own thresholds and templates.

Thresholds vary widely. Common triggers include residential schemes above a set number of homes, developments above a floorspace figure, care and education uses, and specific uses such as hot food takeaways near schools where a local plan has a policy about them.

Check three documents before you decide whether you need one: the adopted local plan policy, the current local validation checklist, and any health and planning supplementary guidance the council has adopted. Councils change validation lists more often than they change plans, so use the version on the website today rather than the one saved from a previous scheme.

Screening and when it stops there

Screening is a structured question set, usually presented as a matrix, that runs through the ways a development could affect health and asks whether an effect is likely, and whether it would be large enough to matter.

A good screening output does three things. It records the answer to each question with a short reason, it identifies which population groups could be affected, and it states a conclusion on whether further assessment is proportionate.

Where the screening shows no likely significant effects, say so and submit the completed matrix as the assessment. Councils accept that outcome when the reasoning is visible. What they do not accept is a matrix ticked negative down the page with no supporting reasoning, and that is the most common reason a screening is sent back.

Screening is also where you catch the scheme-specific issues early enough to design them out, which is the whole point. An HIA that arrives after the layout is fixed can only describe effects, not reduce them.

Rapid against full assessment

The difference is scope and evidence, not format.

Agree the level with the council's public health team before you start. That conversation takes twenty minutes and prevents the outcome nobody wants, which is a rapid assessment submitted where a full one was expected and a request for further information that delays determination.

Determinants of health and the topics to cover

Health impact assessment works through determinants, which are the conditions that shape health outcomes rather than health services themselves. A workable topic list for a residential scheme covers:

• Housing quality, space standards, overheating, daylight and internal noise.
• Access to open space, play space and nature, with distances and quality stated.
• Active travel and connectivity, including walking and cycling routes to schools, shops and public transport.
• Air quality and noise exposure at the proposed dwellings and for existing neighbours.
• Access to healthy food, and the local food environment.
• Employment, training and local economic opportunity during and after construction.
• Social cohesion, community facilities and the design of shared spaces.
• Healthcare and education capacity, and how any pressure is addressed.
• Safety, crime prevention through design, and lighting.
• Climate resilience, including flood risk and summer overheating.

Several of those topics are already covered by other reports in the application. The HIA should draw on them rather than repeat them, so the active travel section should be consistent with the transport evidence and the mode share assumptions discussed in our note on Travel Plan targets and how to evidence them. Where the HIA and the transport report disagree, the officer will notice.

Baseline health data for the area

Use published local sources and cite them by name, geography and year. Local authority health profiles, the joint strategic needs assessment produced by the council and its health partners, census data, and deprivation statistics all give a defensible picture of the population the scheme will serve.

Two disciplines matter. First, match the geography: ward and lower layer super output area data says something quite different from district level data, and a scheme sitting in one deprived ward within an affluent district needs the local figure. Second, describe the population rather than the averages alone, because the point of an HIA is the distribution of effects across groups.

Health equity is where an HIA earns its keep. Identify which groups experience the effects, whether older residents, children, disabled people, people on low incomes or existing neighbours rather than future occupiers. That analysis overlaps with an Equalities Impact Assessment and the two documents should be written together rather than in sequence.

Illustrative example: a 120 home scheme sits in a ward with above average childhood obesity and below average access to green space. The assessment recommends that the on-site open space is designed for informal play and that the pedestrian link to the existing park is delivered in phase one rather than at completion. Both recommendations become conditions. The scenario is illustrative.

Mitigation, monitoring and how the consultee reads it

The public health consultee reads an HIA looking for one thing: whether the recommendations have changed the scheme and whether they are secured. A list of good ideas in an appendix does not change anything.

So write recommendations that can be delivered. Each should name the effect it addresses, the specific design or management response, and the mechanism, whether that is a drawing, a condition, an obligation or a management plan. Where a recommendation was considered and rejected, say why, because a consultee can accept a reasoned rejection more easily than silence.

Monitoring commitments should be proportionate. On most schemes that means monitoring a small number of measurable things, such as travel plan mode share or delivery of open space, rather than promising health outcome data nobody will collect.

PlanScope can draft the Health Impact Assessment structure around your scheme and flag where local baseline data is still needed, and councils usually expect a suitably qualified author, so professional review is strongly advised. The full list of report types shows the other documents a major residential scheme normally requires.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.