I looked through the wikipedia page listing cognitive biases looking for a bias that describes the tendency to assume a poorly understood problem must be simple. Planning fallacy is kind of in the right ballpark; it gets the underestimation part, but I am associating the behaviour with a snap decision more than a plan. Is there another that fits better?

I really thought it would be easy to find this term on wikipedia. I mean, how many psychological terms could there possibly be?

  • $\begingroup$ Well, if that bias exists, I believe I'm often biased to believe the opposite. Possibly an occupational hazard as a software engineer. The more poorly understood a problem is, the less willing I am to make any estimates. What reason do you have to believe this is a common bias? Could you elaborate/reference some specifics? Why are the "snap decisions" relevant in particular, making it somehow different and noteworthy? $\endgroup$
    – Steven Jeuris
    Apr 26, 2019 at 20:11
  • $\begingroup$ Echoing Steven a bit, I feel like the rhetorical "How hard could it be?" is most typically used sarcastically, to acknowledge that what seems like an easy solution on its face is likely anything but (Oh to save Britain we just need to find the Holy Grail. How hard could it be?). $\endgroup$
    – Bryan Krause
    Apr 26, 2019 at 20:32
  • $\begingroup$ Perhaps it doesn't make a difference. As a fellow software engineer, I also attempt to de-bias by planning. It's when I don't plan that I am most likely to fall into this trap. So if planning is how we avoid it, "planning fallacy" doesn't seem to fit. I used the term "snap" to imply not planned. $\endgroup$ Apr 26, 2019 at 20:39
  • $\begingroup$ I am familiar with sarcasm (see "how many psychological terms could there be?"). I also like Monty Python, so thanks for that. $\endgroup$ Apr 26, 2019 at 20:44

3 Answers 3


I believe the closest match is the illusion of control:

... the tendency for people to overestimate their ability to control events; for example, it occurs when someone feels a sense of control over outcomes that they demonstrably do not influence. ... people base their judgments of control on "skill cues". ... When more of these skill cues are present, the illusion is stronger.

This bias only operates when a plausible case can be made for one's skill or intent influencing outcomes - such as a programming task given to a programmer. In such instances, how well the task or problem is understood, its actual level of difficulty, and the actual level of control over outcomes are overestimated or ignored.

Positive illusions - biases that describe how people overestimate their own abilities, success, and control - are the broader category that contains the illusion of control, and the planning fallacy, among others. These biases typically go away when estimating the success of others instead of one's self.

There is another bias worth noting here, called the hard-easy effect:

... a tendency to overestimate the probability of one's success at a task perceived as hard, and to underestimate the likelihood of one's success at a task perceived as easy. ... "Hard tasks tend to produce overconfidence but worse-than-average perceptions," ...

This bias also ignores how well understood a problem is, but it suggests that a problem perceived as hard (whether or not it actually is) is more likely to result in overestimating success. This bias is not as robust or widely accepted as the former.


This sounds a lot like strategic optimism:

When facing performance situations, strategic optimists feel that they will end well. Therefore, though they plan ahead, they plan only minimally because they do not have any anxiety to face. While defensive pessimists set low expectations, feel anxious, and rehearse possible negative outcomes of situations, strategic optimists set high expectations, feel calm, and do not reflect on the situation any more than absolutely necessary.


Since the rhetorical question may include a judgement to others' ability, I think naïve realism and egocentrism are also relevant.

Naïve realism is the human tendency to believe that we see the world around us objectively, and that people who disagree with us must be uninformed, irrational, or biased.

Egocentrism is the inability to differentiate between self and other. More specifically, it is the inability to untangle subjective schemas from objective reality and an inability to accurately assume or understand any perspective other than one's own.


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