Cognitive Scaffold

Preparing your thinking workspace

arrow_back_ios_new
MENTAL MODEL · M4727

Planning Fallacy

Planning Fallacy
Learn & MetacognitionHigh supportCognitive Psychology
Included
account_tree

Updated 2026-08-02

Loading revision record…

INTRODUCTION

English translation pending.

CORE DEFINITION

The planning fallacy describes chronically optimistic forecasts for task completion, even when the same person has overrun similar projects before. Forecasters adopt an internal perspective, focusing on the specifics of the current plan and its best-case path while ignoring the distribution of outcomes from comparable past efforts. The remedy is reference-class forecasting, which uses the actual durations of similar projects as the baseline. Key qualification: the bias affects estimates rather than capability, and it persists even when people know about it.

SCAFFOLDING EFFECT

psychology

Reduce cognitive load

- Baseline first: ask how long comparable tasks actually took before estimating this one. - Use the outside view: treat your project as a member of a class rather than as a unique case. - Build in slack: publish ranges and checkpoints instead of single-point commitments.

anchor

Anchor fast decisions

Planning focuses attention on the specific steps and the intended sequence, which makes the smooth path feel representative. Memory of past overruns is available but not applied, because the current plan feels more detailed and therefore more likely to succeed. The result is a forecast that describes the best case while presenting itself as the expected case.

MINIMUM ACTION

In progress 0/1

Practice this model in one real situation:

Check to track your progress (stored locally)
Learning progress0%
account_treeGenealogyexpand_more
menu_bookReferencesexpand_more

Source support: Explicit

  • link
    zh.wikipedia.orghttps://zh.wikipedia.org/wiki/%E8%A6%8F%E5%8A%83%E8%AC%AC%E8%AA%A4ZH · Explicit
    verified

RELATED MODELS

Related model

Attention Residue

A phenomenon in which attention remains partly on Task A after switching to Task B, potentially impairing information processing and performance on B.

arrow_forwardRelated model

The Forgetting Curve

The Forgetting Curve is a curve used to describe the rate of forgetting in long-term memory. It was first proposed by psychologist Hermann Ebbinghaus based on his experiments conducted from 1880 to 1885. In these experiments, Ebbinghaus used meaningless letter combinations. By memorizing these combinations and checking the forgetting rate after a series of time intervals, he obtained this curve. Therefore, this curve is also called the Ebbinghaus Forgetting Curve.

arrow_forwardRelated model

Baader-Meinhof Phenomenon

The frequency illusion (also known as the Baader–Meinhof phenomenon or Red Car Theory) is a cognitive bias in which a person notices a specific concept, word, or product more frequently after recently becoming aware of it. The name "Baader–Meinhof phenomenon" was coined in 1994 by Terry Mullen in a …

arrow_forward