What makes a good metric?

When it comes to nature and biodiversity, figuring out what to measure is complex. We always strive to meet 7 key criteria when choosing metrics to measure biodiversity and nature.

written by Dr Rhosanna Jenkins, Principal Scientist – Biodiversity

When it comes to nature and biodiversity, figuring out what to measure is complex. With the new TNFD recommendations and the Corporate Sustainability Reporting Directive starting in the European Union from 1st January 2024, how to measure biodiversity is a big question at the moment. Biodiversity is very different from carbon, and so ensuring the metrics and indicators used are valuable is vital.

In this article, we’ll look at 7 key characteristics to consider when deciding which metrics to use for measuring biodiversity.

Biodiversity isn’t the same as carbon

Carbon emissions have a global impact. Emissions released into the atmosphere accumulate around the planet, and it’s this accumulation that impacts climate. Carbon markets, therefore, centre around fungible credits or units. In other words, tonnes of carbon sequestered. This is a simple process as a tonne of carbon sequestered in one location is equivalent to a tonne of carbon sequestered elsewhere.

When it comes to biodiversity, this is not possible.

Location and context are critical, and changes in biodiversity in one location cannot be simply offset halfway around the globe. The impact of changes in nature must be understood in the context of the local ecosystems. This means there is no one-size-fits-all metric for biodiversity and nature reporting.

So how do you measure biodiversity?

Over the years, hundreds of different metrics have been used to study, report, and manage biodiversity and biodiversity change. No one metric is the best, and often it’s worth using multiple metrics at a site.  The world-leading biodiversity credit schemes, such as the Wallacea Trust certification standard, require a minimum of 5 measurable biodiversity metrics per project.

Reporting and risk management frameworks like the Corporate Sustainability Reporting Directive (CSRD) and Taskforce on Nature-related Financial Disclosures (TNFD) suggest metrics that can be used to quantify their recommended indicators. This is often a great place to start.

If you’ve not come across these terms before, an indicator is a descriptor of the type of activity, asset or process to be measured. A metric is a measurement of a specific activity, asset or process. It has an associated unit and time period. A single indicator may be served by multiple metrics.

To track progress towards nature recovery, we must hold metrics to high standards. There are key aspects of good biodiversity metrics that you can use to make your selection.

7 characteristics of a good biodiversity metric


Good metrics should be something that can be measured again and again, over time and space, rather than just providing a snapshot of nature at one moment in time. Repeatable measurements are important for tracking and providing robust evidence of the change in your impacts and dependencies on biodiversity over time. Repeatable metrics can also be used across different geographic areas and spatial scales. This is important for comparing across assets.

If the metric involves you going out and collecting data, it should allow for the data to be collected in a consistent way. Make sure that the data included in any metric you use is defined at the outset and remains consistent.


Metrics should be quantified with units, while not being too difficult to measure. For example, counting all the individuals in a population of birds that live within the boundaries of your asset may seem like a good way of quantifying the state of nature in the area, but this would be incredibly difficult to do in practice.

Without units, it would be extremely difficult to compare measured values in a meaningful way. Where possible, physical units of measurement, such as km2 of natural land converted, should be used.

Data Driven

Metrics should be evidence-based, with a solid theoretical underpinning. It’seasier to communicate the legitimacy of data-driven metrics, demonstrating credibility.

Easily Interpretable

A good metric should be easy to understand, use and communicate. You should ensure that you understand the methods and output of the metric. This is particularly important with geospatially modelled metrics, such as Potentially Disappeared Fraction of species (PDF) or Mean Species Abundance (MSA), which are built on a range of assumptions and technical decisions.

Metrics should also be representative of the impact/level of concern. When the metric value changes, the impact should change similarly.


Metrics should reliably respond to changes in the way you were expecting. This means metrics can be better linked to actions and outcomes and can support target setting. And that it is possible to assess in advance how actions will affect the metric.


This means it can’t be gamified. And metrics should not be used to simply “tick a box”.

Sensitive to changes

The more sensitive the metric, the more actionable the metric is. Good metrics for biodiversity should be sensitive enough to capture meaningful change.

An example of a good metric

At natcap we strive to meet all 7 of the criteria above as a minimum. To demonstrate a simple example using one of our metrics, let’s look at “Percentage of natural lands”.

We measure the percentage of natural lands using satellite data. As the satellite passes over every point on the surface of the Earth regularly this measurement is very repeatable. The percentage is measured by comparing the amount of land on a site which is covered in natural vegetation, such as trees, shrubland, marshland, and that which is not natural, such as buildings or crops. This measurement is very much data driven and not qualitative or subjective. It is easy to interpret as the result is a number summarising the percentage of land on a site which is natural. It is predictable and sensitive to change - if you were to plant more trees on a site then the next time you measure the percentage of natural land then it will have increased. It is very hard to gamify this metric, you can’t fudge the numbers to make there be more trees, making it robust.

Help is at hand...

Picking metrics for nature reporting is a challenge, but these criteria can help sort through the options. Not all metrics will be able to satisfy all these characteristics, but you should strive to meet as many criteria as possible.

At natcap, we help organisations measure and manage your interface with nature using up to 25 different metrics. We specifically select the metrics for your business needs and ensure they help you make informed business decisions to reduce risks and utilise opportunities.

Get in touch to see how easy it is to start measuring your impact on nature.

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