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Health Impact Assessment (HIA) process

The process routinely consists of several main steps. Whilst some may think of it as a linear process, HIAs are iterative processes. It is sensitive to evidence, timescales and circumstances. For example, the scope of a HIA should be kept under review as new information may emerge during the later steps of the process.

Transcript – The Health Impact Assessment HIA process in Wales

Now that you understand what Health Impact Assessment is and why it matters, let’s explore how the process works in practice here in Wales.

HIA is a flexible process that helps assess how a proposed policy, decision, or project could impact on people’s health and wellbeing. It’s not just about physical health — it also looks at mental health, social, economic, cultural and environmental influences.

In Wales, the HIA process follows five key steps: screening, scoping, evidence appraisal, reporting and recommendations, and review and reflection, including monitoring and evaluation.

Step 1: Screening

Screening is the first step of the HIA process and helps determine whether an assessment is needed. It considers the potential impacts of a proposal on health, wellbeing, and equity, including how different population groups might be impacted.

Step 2: Scoping

The scoping step helps set the boundaries — deciding how long the HIA will take, what resources are needed, any important deadlines, and what evidence should be collected and reviewed.

Step 3: Evidence Appraisal

The appraisal step involves gathering and analysing evidence. This can include quantitative and qualitative data, existing research, and the views of key stakeholders and people with lived experience — especially those who may be most impacted.

Step 4: Reporting and Recommendations

Findings are brought together into a report that outlines potential short and long term impacts on people and the wider determinants of health. Recommendations are also provided to reduce harm and maximise benefits. This helps inform decision-makers before any action is taken.

Step 5: Review and reflection, including monitoring and evaluation

The final step is to monitor what happens after the decision. Evaluation checks whether recommendations were followed and whether the intended outcomes have been achieved. It also supports learning for future HIAs.

Each step ensures health, well-being and equity are considered in the decisions that shape our communities — supporting the Well-being of Future Generations Act and creating a healthier Wales for everyone.

To learn more, or access tools and guidance, contact the Wales Health Impact Assessment Support Unit at Public Health Wales.

  1. Step 1:Screening

    Considering whether the proposal has an impact on health, well-being or equity, and if so, considering who it affects and how.

  2. Step 2:Scoping

    Defining the parameters of the HIA, how long will it take, what resources it will require, noting any deadlines, and thinking about what evidence should be gathered and appraised.

  3. Step 3:Evidence appraisal

    Assessing the evidence gathered by synthesising and analysing it to form a picture of impact. This evidence can include peer reviewed and grey literature, stakeholder evidence and routinely gathered data or statistics.

  4. Step 4:Reporting and recommendations

    Construction of a report which includes an outline of the process, findings and any recommended action that should be taken to maximise the positive impact and mitigate any negative impact*.

    *Quality Assurance – This should be incorporated into the reporting step, or post publication. It enables a review of the HIA to be carried out to ensure confidence in the content, findings and robustness of the process of the HIA.

  5. Step 5:Review and reflection, including monitoring and evaluation

    Highlighting milestones to measure any changes in impact or if the predicted impacts were observed, reviewing the process and any impact which it may have had on decisions and future policies.

For more information on how to carry out a HIA, see the HIA practical guide.

Types of HIA

HIA is proportionate to the context and the degree of complexity of the proposal under assessment. 

There are two different types of HIA practiced in Wales. It is possible for a HIA to fit between two types, using elements of each type, determined by the nature of the proposal being assessed:

  1. Rapid (a ‘standard’) HIA
  2. Comprehensive HIA

The difference between a Rapid (standard) HIA and a Comprehensive HIA mainly lies in their depth, scope, time requirements, and resource utilisation. In summary, a Rapid (Standard) HIA is quicker and less resource-intensive than a Comprehensive HIA and is focussed on providing timely insights with a narrower scope of analysis. In comparison, Comprehensive HIAs are more detailed, time-consuming and resource intensive allowing for in-depth analysis and participation.

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