When does a digital twin stop telling the truth?

Digital twins have transformed the way we understand, manage and interact with physical assets.

We invest significant time and money creating increasingly accurate digital representations of roads, infrastructure, buildings and networks.

But there is a problem.

The physical world doesn’t stand still.

From the moment a digital twin is created, the asset it represents continues to change.

Something gets repaired. Something deteriorates. A barrier is moved. Vegetation grows. A defect appears. An inspection takes place. Temporary works are installed and removed. Someone makes a decision based on what they saw at that moment.

The digital representation may still look perfectly convincing.

But is it still telling the truth?

The problem of digital decay

We tend to think about the accuracy of a digital twin at the point it is created.

Perhaps we should also be thinking about its accuracy through time.

Every change in the physical environment that is not reflected in the digital environment creates a little more distance between the two.

That is digital decay. And the longer that gap exists, the harder it becomes to answer some surprisingly simple questions.

• What was actually there?

• When did it change?

• What condition was it in?

• Was it inspected?

• What was identified?

• What action was taken?

And crucially,

• can we prove it?

Perhaps the missing dimension is evidence

Keeping every digital representation continuously updated may not always be practical, necessary or economically sensible. But preserving evidence of change may be.

Imagine being able to revisit an asset, route or operation not simply as it exists today, but through the evidence accumulated around it over time.

Every inspection. Every image. Every observation. Every action.

A searchable, traceable history that provides context around the digital representation and helps explain how today became today.

That starts to change the role of the digital twin.

It is no longer simply a representation of an asset.

It becomes part of a much richer record of its history.

From Digital Twin to Evidence Twin

This thinking led us to a concept we call the Evidence Twin.

An Evidence Twin does not replace a digital twin. It complements it by preserving the evidence surrounding an asset, route or operation over time, creating a living, searchable and auditable history of what happened.

Perhaps the next evolution of digital twins isn't simply about creating ever more accurate representations of the physical world.

Perhaps it is about making sure we can still understand and evidence what happened between the snapshots.

Because knowing what something looks like today is valuable.

Knowing how it got there may be even more important.