What's in a name? On indicators, measures and metrics

Working on the upcoming study on Indicator Development, Selection and Use Principles for Climate Change Adaptation M&E I was reading through a wide selection of adaptation M&E frameworks. After a while I started to notice the different ways in which authors talked about indicators, measures and metrics. The definitions of the terms 'indicator', 'measure' and 'metric' vary across agencies and are often used interchangeably, though there are subtle differences. It is useful to check in advance how these terms are used within different contexts.

Reading a business blog on KPI's by Phil Jones I felt it was time to create some clarity in indicator-related concepts and definitions!

A measure is a value that is quantified against a standard. A project implementer wants to know that the total urban green space being developed is 250 acres in size. There is the standard 'acres' in there and we can all see and agree how big it is.

The urban planner on the other hand wants to know that the urban green space developed supports a city growth by 22,780 inhabitants (he calculates with 500 square feet of urban green space per new inhabitant). The number of 22,780 inhabitants is an indicator of size for the green space, but not a measure because it does not adhere to a universally agreed standard.

According to OECD/DAC, an indicator is: "A quantitative or qualitative factor or variable that provides a simple and reliable means to measure achievement, to reflect changes connected to an intervention, or to help assess the performance of a development actor". (OECD/DAC Glossary of Key Terms in Evaluation and Results Based Management, May 2002)

According to the definition adopted by USAID, an indicator is: "A quantitative or qualitative variable that provides reliable means to measure a particular phenomenon or attribute". (USAID Glossary of Evaluation Terms, March 2009)

What is more useful?! 'measure' or 'indicator'?

What is more useful, 'measure' or 'indicator', really depends on the perspective. To the project implementer the standard measure of 250 acres is most useful. Knowing the number of new inhabitants it will serve does not help him when he orders trees and grass seed. On the other hand, the specific measure does not matter to the urban planner ? he wants to know the number of new inhabitants it will support. In that sense, the ?measured? size, what is measurable against a standard, is not always the most useful.

An objective measure must serve purpose and use. It must accurately measure what we want to know. An indicator gets close to, approximates the qualities, but not to a necessarily agreed standard. We have to acknowledge that especially in climate change adaptation there aren't that many agreed universal standards and ?measures of success? will as such often be indicators.

In the study on Indicator Development, Selection and Use Principles for Climate Change Adaptation M&E we will be talking about indicators, even if these are quantitative and measured against standardized units (ie. a measure) or represent a composite or multi-dimensional structure of data (ie. a metric).

But what is a metric?

What does the size of 250 acres tell us? Is that a lot of urban green space? And is 500 square feet of green space per inhabitant a good deal? 'Yearly growth in urban green space for 2004 ? 2014' would be a metric. The 'urban green space per inhabitant for the 10 biggest US cities in 2004' is also a metric.

A metric is a calculated or composite measure or quantitative indicator based upon two or more indicators or measures. Metrics help to put a variable in relation to one or more other dimensions.

Let us know how your organization talks about indicators!

Does this blog post reflect the line of thinking within your organization? Or does your organization, or do you, have completely different ideas? Let us know!