How many times have you heard someone complain, “It’s like comparing apples and oranges”? The statement is always definitive and implies that the group should move on from an illogical discussion—because everyone knows that an apple can’t be compared to an orange.

But have you ever stopped to ask whether an apple can be compared to an orange?

Of course they can be compared. One is green; the other is orange. Both are round. One can be bitten into, the other requires knife. Both are sweet. One has a core, the other has segments. Both are fruits.

See, I just compared an apple and an orange.

In the field of sustainability reporting, we fall into the apple and orange trap far too easily.

We can’t compare a company doing its own manufacturing with one that outsources its manufacturing, the complaint goes, “because that’s comparing apples and oranges.”

We can’t compare a company holding vast amounts of personal data with one that does not, the complaint goes, “because that’s comparing apples and oranges.”

Let’s take greenhouse gas emissions as an example of why this is wrong.

If sustainability report readers were to look just at the Scope 1 (direct) and Scope 2 (indirect) emissions and conclude that the company with the lower number must be performing better and present lower risks, then I would have some sympathy with the apples and oranges defense.

But this is not how readers should or do read sustainability reports. It’s not the number alone that matters; it’s the combination of the quantitative number and the accompanying qualitative narrative that provides the full picture.

The company with outsourced manufacturing will have lower Scope 1 and 2 emissions, but could face significant climate impacts and risks in its supply chain. The company doing its own manufacturing will have higher Scope 1 and 2 emissions but may be in more complete control of its climate resilience.

The point is that, when written well, sustainability reports allow readers to draw this comparison and make informed decisions accordingly.

A quantitative key performance indicator (KPI) enables effective comparison with other companies only when accompanied by a key performance narrative (KPN) setting out the various business models, sustainability context, or business strategy factors that may impact the interpretation of the KPI. In other words, the context matters.

Sustainability reporting is better when we do compare apples and oranges and decide whether we prefer to eat the apple or the orange, or want to mix them together in a fruit salad. Sustainability reporting is all about comparing apples and oranges.

Indeed, a NASA researcher did compare an apple and an orange once, and concluded that “the comparing apples and oranges defense should no longer be considered valid.” He termed it a “startling revelation” that could have a “dramatic effect on the strategies used in arguments and discussions in the future.”

So, the next time someone complains that you can’t compare an apple and an orange, be the savior of the meeting by saying that you can.