The Dunning-Kruger effect states that people unexperienced in a certain field or subject generally perceive themselves as having greater aptitude than in reality they do. Dunning and Kruger were able to quantify this using test-scores in their original paper, but popular expositions typically generalize this in a way consistent with the following plot:

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As a layman, this form is more interesting to me because it is more generally applicable, but it also suffers from some drawbacks:

  1. How should experience/confidence be gauged or measured? Is there a general way to do this which doesn't rely on test scores?

  2. Suppose experience is measured in hours spent on the subject. Is there an approximate number of hours at which the peak is reached? The minimum? If so what are these numbers?

If an answer to either (but especially 2) is possible or available, it will help conscientious newcomers to any subject estimate the amount of time needed before trusting a self-evaluation of their competency.

  • $\begingroup$ I don't have time to respond properly, however the attached article touches on this. What I will say briefly is your going to have to either test them some how, or record their level of education or years working within a particular subject. You have to operationalise the variables. There is no peak expertise, or number of hours expertise this has been scientifically debunked. pdfs.semanticscholar.org/8226/… sciencedirect.com/science/article/pii/S0160289614000087 $\endgroup$
    – Comte
    Jan 26, 2017 at 13:34
  • $\begingroup$ @Comte thanks for the comment. I believe castonline.ilstu.edu/smith/405/readings_pdf/… Is a similar article by the same author available to the wider public. I understand the comment, but meant "experience in hours" to simply be a heuristic which is easily measurable. I understand the debate on innate vs learned talents is not settled. By the peak I meant the peak of confidence (maximum of the curve). Whether peak confidence without ability occurs under some typical number of hours is the crux of the question. $\endgroup$
    – JMJ
    Jan 26, 2017 at 16:33
  • 1
    $\begingroup$ Has the graph been edited? Because the left-hand x axis label should surely read 'Know nothing' rather than 'no nothing' $\endgroup$
    – Peter
    Jan 27, 2017 at 13:02
  • $\begingroup$ @Peter. Got it from the Internet, but now I see that haha. $\endgroup$
    – JMJ
    Jan 27, 2017 at 16:03
  • $\begingroup$ There is a nice TED talk on learning. To become an expert, it is typically said you need 10.000 hours, which could be the right peak. Here is the entire talk, where he argues that any skill can be learned in 20 hours: youtube.com/watch?v=5MgBikgcWnY $\endgroup$ Feb 3, 2017 at 14:55

1 Answer 1


Premise: I understand that the question is how to gauge (that is, to create a measure) or to assess expertise in something.

Answer 1.

Some criteria (very loosely translated from Hacker, 2005, pp. 381):

  • issue-specific knowledge;
  • general knowledge about the topic of expertise combined with problem-solving heuristics ranging across specific issues of this very topic;
  • knowledge of ideal courses of action;
  • conscious reflectiveness on the adequacy of task execution;
  • metacognitive ability (e.g. internalized, automated execution involving also motivation, emotional intelligence etc.);
  • ability to solve new kinds of problems related to the topic of expertise.

Answer 2.

No, there aren't any general numbers since it is not possible to define them without referring to both a specific topic of expertise and the predisposition of the person aiming to become an expert.

While I am not aware of any research to support this claim empirically, I maintain that a logical argument can suffice: How long will it take the same individual to acquire expertise as a surgeon compared to acquiring expertise at peeling potatoes?

Moreover, the development of confidence over time is closely tied to both the frequency and the quality of feedbacks about ones' success at doing something in the real world (Hacker, 2005).

Note: Unfortunately the cited work is written in German. A not as extensive English language replacement for it is Hacker (2003).


Hacker, W. (2003). Action Regulation Theory: A practical tool for the design of modern work processes? European Journal of Work & Organizational Psychology, 12(2), 105. https://doi.org/10.1080/13594320344000075

Hacker, W. (2005). Allgemeine Arbeitspsychologie: psychische Regulation von Wissens-, Denk- und körperlicher Arbeit. Bern: Huber.


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