Marine toolbox

Showing significance

Project Timing

Delivering project studies


Screening and executing the ESIA

Issue Addressed

Poor transparency of decision-making and inability to validate conclusions

What is happening?

Often ESIA reports lack transparency on how conclusions are drawn even though existing guidance aims to deliver this. There is also often a lack of consistency on how impact significance conclusions are drawn within reports. In addition, significance can be determined broadly by ESIA consultants in a way that does not pay full attention to detail or does not address inherent weaknesses in understanding. Finally, there is often a lack of transparency in ESIA Reports on how significance has been determined on an impact-by-impact basis even when methodologies are provided.

Why is it a problem?

Poor transparency, non-consistent approaches and difficulty in being able to verify ESIA conclusions means that decisions could be made without a full and detailed understanding of impacts. Sometimes correct conclusions are not drawn with obvious risks to businesses and the environment.

How do we help to solve it?

We have developed a simple tool to help address these problems. The purpose of the tool is to provide a software platform for the assessment of significance once all of the evidence has been gathered. Use of the tool ensures that impact significance is measured consistently through the use of a standard systematic scoring system. The tool allows for the assessment of each individual impact to be saved as an image, which creates a precise record of how conclusions have been drawn. This provides evidence on how impact has been determined if shared in reports for each impact considered. This information can be easily verified by third parties who can also use the calculator to form an independent opinion for cross-reference. Another important benefit is that using the tool should promote ESIA consultants to think carefully about how they input into the tool. This helps ESIA consultants to understand where there may be weaknesses in understanding and uncertainties, which can also be communicated within reports more clearly. It is expected that the use of the tool on an impact-by-impact basis will promote ESIA consultants to justify each input in reports and provide a clear description of why conclusions have been drawn, which would significantly improve transparency; but also improve how impact assessments are undertaken.

EIA calculator to help determine impact significance

The software provides a consistent and transparent methodology for determining the significance of environmental impacts and can be adopted as part of screening studies, strategic assessments or full impact assessments. This tool also provides a framework to build understanding on how to determine impact significance for use by EIA practitioner’s, educators, students and decision-makers. It is both an assessment and validation tool.

The aim is not to replace existing thematic guidelines for EIA approaches, but to add to these by drawing out a transparent way of forming conclusions. The aim is not to replace thematic guidelines for EIA approaches that exist, but to add to these by drawing out a transparent way of forming conclusions across all themes addressed. EIA approaches can therefore continue to follow existing guidelines for thematic EIA approaches where they exist and use the calculator to finalise how significance is determined. The calculator also aims to provide a standard approach for themes where there are no guidelines available on how to determine impact significance.

Further guidance is provided in the ‘Read Me’ pdf document, which is available for download and is also embedded within the software interface.


Please complete the form to download the free EIA Calculator software.

After completing the form the download should start automatically.

EIA Calculator.
Version: 2.1.
File Size: 862KB

System Requirements:
Windows XP, Windows 7, Windows 8 (.NET required)

EIA Calculator Read Me (pdf)


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