What are weak signals?

A simple definition

A weak signal, or signal of change, is a concrete observation of something new, unusual or out of place that could point to a larger change. It is called "weak" because it is still small: it shows up in few places, hardly anyone talks about it and it is easy to miss.

It is not an opinion or a prediction. It is a fact you can describe: a sign, a conversation, a service that appears or disappears, a habit that changes.

Where the idea comes from

The concept was proposed by the economist Igor Ansoff in 1975, while studying how companies could anticipate strategic surprises. His point was that big changes rarely arrive without warning: they usually leave small traces first. Today, spotting signals is a core practice of foresight, the discipline that explores possible futures.

Everyday examples

These examples help you recognize what kind of thing a signal is; they are not findings or studies.

• A market stall puts up a handwritten sign: "Phone payments only, no cash."
• At a mototaxi stop, a driver offers to charge phones with a small solar panel.
• A teacher sends homework as voice notes because several families have no data to download files.
• In a flood-prone area, families raise their houses weeks earlier than usual.

How to recognize a signal

A good signal usually meets several of these conditions:

• It is concrete: you can say what you saw, where and when.
• It surprises you or seems out of place.
• It is new or growing: it was not there before, or it was rarer.
• It opens a question: "if this spreads, what else could change?"

Why they matter

A single signal proves nothing. But when many people, in different places, record similar signals, patterns begin to emerge: emerging trends, shifting values, new needs. Noticing them early lets us prepare, seize opportunities or decide which future we want to avoid.