Ladder of Inference

The ladder of inference is a key tool of Action Science—one approach to action research. The ladder is a model of our reasoning steps as we assess a situation and decide what action to take (Figure 1). This entry describes the features of the ladder and how it can be used to help people reflect on their behaviour and the reasoning behind it.

Figure 1 Ladder of Inference: How We Think

At the bottom of the ladder are the available data: numbers on a spreadsheet, the content of a memo, [Page 487]what others say, their non-verbal behaviour and so on. Given the limits of the mind, humans cannot pay attention to everything. They select, often without being aware of it, the information that is most salient and ignore the rest (first rung). Next, they interpret what that data means (second rung), and from these meanings, they draw conclusions: They evaluate, explain, make predictions and decide what to do (third rung). Based on the decisions they make, they then take action, and these actions become part of the data pool from which they draw further inferences. This is particularly important in interpersonal interaction. While they are typically aware of how others' actions affect them, individuals are often not aware of their own actions and their impact on others. Yet the actions they take become data that others use to make inferences, attributions and evaluations about them, which may be different from what those individuals hope for or intend.

Chris Argyris developed the ladder of inference as a tool for double-loop learning—learning that produces change in values and assumptions, not simply behaviour change. Initially developed for research and intervention, it is useful for anyone engaged in a difficult conversation where the quality of the conversation is critical for effective action. While there are alternative versions of the ladder of inference in the literature, all of them have a common focus and purpose: how people make inferences and the need to make inferences explicit so that errors in reasoning can be discovered and corrected.

A premise of Action Science is that any action with an intended consequence is informed by reasoning, and the effectiveness of action depends on the quality of reasoning. The difficulty with improving reasoning is that it is often invisible. Individuals ‘go up our ladder’ so quickly—at the speed of thought—that they are not aware of their interpretations and inferences. Their conclusions feel obvious; therefore, they see no need to check the validity of the conclusions.

How individuals move up their ladders of inference—from data to interpretations, to conclusions—is not random or accidental. Their inferences are influenced by past experience, current context, emotional state, values and assumptions. For example, in some cultures, arriving at a meeting after the scheduled start time is considered late and is reprimanded. In others, it goes unnoticed. If a subordinate says, ‘We need to do X to solve Y’, it is a request for resources. If the boss says the same, she is giving orders.

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