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when people forecast how long it will take them to complete a project, the mean of their estimates is usually much lower than the time they will actually need.
planning fallacy.
The theory of judgment heuristics proposes that people will sometimes use the answer to an easier question in responding to the harder one.
heuristic for answering a difficult question is to find the answer to an easier one.
Errors are bound to occur when a judgment of similarity is substituted for a judgment of probability,
Taking the outside view can make a large difference and prevent significant errors.
Substituting a judgment of how easily examples come to mind for an assessment of frequency is known as the availability heuristic.
For example, a full answer to a question about life satisfaction clearly requires consulting more than your current mood, but evidence suggests that mood is in fact overly weighted.
substituting similarity for probability leads to neglect of base rates,
In that case, the evidence will be selective and distorted: because of confirmation bias and desirability bias, we will tend to collect and interpret evidence selectively to favor a judgment that, respectively, we already believe or wish to be true.
The psychologist Paul Slovic terms this the affect heuristic: people determine what they think by consulting their feelings.
regardless of the true reasons for your belief, you will be inclined to accept any argument that appears to support it, even when the reasoning is wrong.
subtler example of a conclusion bias is the anchoring effect,
Anchoring is an extremely robust effect and is often deliberately used in negotiations.
illustrates excessive coherence: we form coherent impressions quickly and are slow to change them.
(Another term to describe this phenomenon is the halo effect,
In general, we jump to conclusions, then stick to them. We think we base our opinions on evidence, but the evidence we consider and our interpretation of it are likely to be distorted, at least to some extent, to fit our initial snap judgment.
substitution biases, which lead to a misweighting of the evidence; conclusion biases, which lead us either to bypass the evidence or to consider it in a distorted way; and excessive coherence, which magnifies the effect of initial impressions and reduces the impact of contradictory information.
matching: your task is to find a value on the judgment scale that matches your mood or experience.
Conflicting cues make it more difficult to achieve a sense of coherence and to find a judgment that is a satisfactory match.
Your System 1 simplifies a difficult prediction question by answering a much easier one:
Substituting one question for another inevitably causes errors when the true answers to the two questions are different.
examples of matching predictions are more likely than not to end in disappointment.
System 1 proposes quick associative solutions to problems as they arise, but these intuitions must be endorsed by the more reflective System 2 before they become beliefs.
We offer the outside view as a corrective for intuitive predictions of all kinds.
The outside view can be neglected only in very easy problems, when the information available supports a prediction that can be made with complete confidence. When serious judgment is necessary, the outside view must be part of the solution.
There is a genuine limit on people’s ability to assign distinct labels to stimuli on a dimension, and that limit is around seven labels.
Categorization is not under voluntary control when you are in the fast-thinking mode.
Our ability to compare cases is much better than our ability to place them on a scale.
Explicit comparisons between objects of judgment support much finer discriminations than do ratings of objects evaluated one at a time.
Comparative or relative judgments are more sensitive than categorical or absolute ones.
A procedure that compels explicitly comparative judgments is likely to reduce noise.
People may differ in their judgments, not because they disagree on the substance but because they use the scale in different ways.
Ambiguity in the wording of scales is a general problem.
simplify the task by substituting an easy question for the hard one.
level noise is the variability among jurors in how severe they are in general. Pattern noise is the variability in how a given juror responds to particular cases, relative to this juror’s own average.
The lack of clarity on the upper end of the scale makes some noise inevitable.
people are much more sensitive to the relative value of comparable goods than to their absolute value.
First, the choice of a scale can make a large difference in the amount of noise in judgments, because ambiguous scales are noisy. Second, replacing absolute judgments with relative ones, when feasible, is likely to reduce noise.
The rule is simple: if there is more than one way to see anything, people will vary in how they see it.
confidence in one’s judgment by no means guarantees accuracy.
behaviors are a function of personalities and of situations.
level noise—or simple, across-the-board differences between judges—should be a relatively easy problem to measure and address.
Reducing level noise is still a worthwhile objective, but attaining only this objective would leave most of the problem of system noise without a solution.
The key to this puzzle is that although the average of errors (the bias) and the variability of errors (the noise) play equivalent roles in the error equation, we think about them in profoundly different ways.
A well-documented psychological bias called the fundamental attribution error is a strong tendency to assign blame or credit to agents for actions and outcomes that are better explained by luck or by objective circumstances.
Noise is inherently statistical: it becomes visible only when we think statistically about an ensemble of similar judgments.
Causally, noise is nowhere; statistically, it is everywhere.
Causes are natural; statistics are difficult. The result is a marked imbalance in how we view bias and noise as sources of error.
bias is a compelling figure, while noise is the background to which we pay no attention. That is how we remain largely unaware of a large flaw in our judgment.
