Decision context

Project estimation & delivery

Use these evidence-reviewed lenses when setting a deadline, estimating effort, discussing delivery risk, or learning from a project that finished later than expected.

Use this context when

Start from the situation, not a label.

A deadline is being built from a detailed plan without checking how long similar work actually took.
An early target, budget, or rough estimate is pulling later discussion toward the same number.
A team is debating one precise date even though important dependencies and unknowns remain.
A project is already late and the new estimate is again starting from the ideal plan.
Delivery risk is discussed as one broad feeling instead of explicit ways the plan could slip.
After delivery, the final outcome is changing what people remember about the original estimate.

Evidence-reviewed lenses

6 patterns worth testing, not diagnosing.

well-supported for time estimates; size and causes vary by contextEvidence

Planning Fallacy – when plans make completion times look too optimistic

What happened on the most comparable completed work, and why should this case be faster or slower?

The planning fallacy is a well-documented tendency for people to predict their own task completion times too optimistically. The effect has been observed across different kinds of tasks, but it is not a rule that every plan will run late. Project overruns can also come from changing scope, dependencies, incentives, poor data, deliberate underestimation, or genuinely unusual events, so a late project should not automatically be diagnosed as a planning fallacy.

Read evidence review Use in Decision Audit →

well-supported for numerical judgments; strength depends on anchor type and contextEvidence

Anchoring Effect – when a starting number pulls later estimates toward it

Which early number is shaping this estimate, and what would we estimate if we had not seen it first?

Anchoring is a well-supported effect in which an initial numerical value can pull a later estimate toward it. A 2026 meta-analysis covering 2,601 effect sizes found a large overall effect, but also substantial variation across studies. The effect should not be treated as a rule that every number changes every judgment: incidental anchors, anchors from a different dimension, clearly random values, incentives, and some debiasing conditions were associated with smaller or null effects.

Read evidence review Use in Decision Audit →

established with boundary conditionsEvidence

Subadditivity Effect – the whole seems less likely than the sum of its parts

Does the risk estimate change when we unpack the main ways the project could be delayed?

People often give a larger total probability when an event is unpacked into separate possibilities than when the same event is judged as one packed category. The effect is not universal: how the possibilities are described and how typical they are can change or even reverse an unpacking effect.

Read evidence review Use in Decision Audit →

established heuristic; bias is context-dependentEvidence

Availability Heuristic – when easy-to-recall examples shape frequency judgments

Are we using a vivid recent project as the baseline because it is representative, or simply because it is easy to remember?

Availability is a judgment heuristic: people can use how easily examples or scenarios come to mind when estimating frequency or probability. That shortcut is not automatically an error because memorable or accessible examples can correlate with real frequency. Bias appears when accessibility is driven by factors that are not diagnostic of the quantity being judged.

Read evidence review Use in Decision Audit →

robustEvidence

Hindsight Bias – when the past looks obvious in retrospect

What did the original estimate and assumptions actually say before we knew the delivery result?

Knowing an outcome can make the outcome look more predictable in retrospect. The effect has been studied for decades and across many settings, but it does not mean that every confident explanation after an event is biased.

Read evidence review Use in Decision Audit →

established, but related constructs should be separatedEvidence

Escalation of Commitment – when setbacks lead to more investment in the same course

If we were deciding only about the remaining work today, would we still choose the same next step?

Sunk-cost effects and escalation of commitment overlap but are not interchangeable. Sunk-cost research asks whether irrecoverable prior investments influence current choices. Escalation of commitment describes persistence or additional resource allocation to a failing course of action and can also be driven by personal responsibility, self-justification, project structure, and other factors.

Read evidence review Use in Decision Audit →

Decision workflow

Turn the context into observable questions.

1
Start with comparable completed work. Write down what similar tasks actually took before refining the current plan.
2
Check whether a target, budget, or early rough number became an anchor. Build an independent estimate when possible before reconciling the two.
3
Give a useful range and explain what would push delivery toward the earlier or later end.
4
Unpack the main ways the plan can slip instead of hiding all uncertainty inside one confidence number.
5
Record the estimate, assumptions and important unknowns before work starts so the later review has a real baseline.
6
When the plan changes, judge the next step on future cost and value rather than on how much has already been spent.

Open a blank Decision Audit

Practice this context

Can you match the question to the lens?

Open 6 practice exercises