Unbiased Analysis of Today's Healthcare Issues

Useful mental models

Written By: Jason Shafrin - Aug• 16•16

Gabriel Weinberg, CEO of DuckDuckGo, has a list of mental models that he believes “come up repeatedly in day-to-day decision making, problem solving, and truth seeking.”   Many are from the world of economics, but I focus on non-economic models as well.  I organzie them into categories based on how Weinberg did in his post. I have highlighted a 2-3 in each category that I think are most interesting/novel.


  • Hanlon’s Razor — “Never attribute to malice that which is adequately explained by carelessness.”
  • Arguing from First Principles — “A first principle is a basic, foundational, self-evident proposition or assumption that cannot be deduced from any other proposition or assumption.”
  • Proximate vs Root Cause — “A proximate cause is an event which is closest to, or immediately responsible for causing, some observed result. This exists in contrast to a higher-level ultimate cause (or distal cause) which is usually thought of as the ‘real’ reason something occurred.” (related: 5 whys — “to determine the root cause of a defect or problem by repeating the question ‘Why?’)


  • Power-law — “A functional relationship between two quantities, where a relative change in one quantity results in a proportional relative change in the other quantity, independent of the initial size of those quantities: one quantity varies as a power of another.” (related: Pareto distribution;Pareto principle — “for many events, roughly 80% of the effects come from 20% of the causes.”
  • Pareto Efficiency — “A state of allocation of resources in which it is impossible to make any one individual better off without making at least one individual worse off…A Pareto improvement is defined to be a change to a different allocation that makes at least one individual better off without making any other individual worse off, given a certain initial allocation of goods among a set of individuals.”


  • Critical Mass — “The smallest amount of fissile material needed for a sustained nuclear chain reaction.” “In social dynamics, critical mass is a sufficient number of adopters of an innovation in a social system so that the rate of adoption becomes self-sustaining and creates further growth.”
  • The Structure of Scientific Revolutions — “An episodic model in which periods of such conceptual continuity in normal science were interrupted by periods of revolutionary science. The discovery of “anomalies” during revolutions in science leads to new paradigms. New paradigms then ask new questions of old data, move beyond the mere “puzzle-solving” of the previous paradigm, change the rules of the game and the “map” directing new research.”  [See also this excellent book]


  • Selection Bias — “The selection of individuals, groups or data for analysis in such a way that proper randomization is not achieved, thereby ensuring that the sample obtained is not representative of the population intended to be analyzed.” (related: sampling bias)
  • Response Bias — “A wide range of cognitive biases that influence the responses of participants away from an accurate or truthful response.”
  • Observer Effect — “Changes that the act of observation will make on a phenomenon being observed.” (related: Schrödinger’s cat)
  • Survivorship Bias — “The logical error of concentrating on the people or things that ‘survived’ some process and inadvertently overlooking those that did not because of their lack of visibility.”


  • False Positives and False Negatives — “A false positive error, or in short false positive, commonly called a ‘false alarm’, is a result that indicates a given condition has been fulfilled, when it actually has not been fulfilled…A false negative error, or in short false negative, is where a test result indicates that a condition failed, while it actually was successful, i.e. erroneously no effect has been assumed.”
  • Bayes’ Theorem — “Describes the probability of an event, based on conditions that might be related to the event. For example, suppose one is interested in whether a person has cancer, and knows the person’s age. If cancer is related to age, then, using Bayes’ theorem, information about the person’s age can be used to more accurately assess the probability that they have cancer.” (related: base rate fallacy)
  • Regression to the Mean — “The phenomenon that if a variable is extreme on its first measurement, it will tend to be closer to the average on its second measurement.”
  • Simpson’s Paradox — “A paradox in probability and statistics, in which a trend appears in different groups of data but disappears or reverses when these groups are combined.”


  • Local vs Global Optimum — “A local optimum of an optimization problem is a solution that is optimal (either maximal or minimal) within a neighboring set of candidate solutions. This is in contrast to a global optimum, which is the optimal solution among all possible solutions, not just those in a particular neighborhood of values.”
  • Confirmation Bias — “The tendency to search for, interpret, favor, and recall information in a way that confirms one’s preexisting beliefs or hypotheses, while giving disproportionately less consideration to alternative possibilities.” (related: cognitive dissonance).
  • Availability Bias — “People tend to heavily weigh their judgments toward more recent information, making new opinions biased toward that latest news.”


  • False Cause — “Presuming that a real or perceived relationship between things means that one is the cause of the other.” (related: correlation does not imply causation, or in xkcd form)
  • Straw Man — “Giving the impression of refuting an opponent’s argument, while actually refuting an argument that was not advanced by that opponent.”
  • Appeal to Emotion — “Manipulating an emotional response in place of a valid or compelling argument.”
  • Ad Hominem — “Attacking your opponent’s character or personal traits in an attempt to undermine their argument.”
  • Bandwagon — “Appealing to popularity or the fact that many people do something as an attempted form of validation.”


  • The Third Story — “The Third Story is one an impartial observer, such as a mediator, would tell; it’s a version of events both sides can agree on.”
  • Active Listening — “Requires that the listener fully concentrates, understands, responds and then remembers what is being said.”
  • Best Alternative to a Negotiated Agreement (BATNA) — “The most advantageous alternative course of action a party can take if negotiations fail and an agreement cannot be reached.”


  • Weekly 1–1s — “1–1’s can add a whole new level of speed and agility to your company.”
  • Pygmalion Effect — “The phenomenon whereby higher expectations lead to an increase in performance.” (related: market pull technology policy — where the government sets future standards beyond what the current market can deliver, and the market pulls that technology into existence.)
  • Consequence vs Conviction — “Where there is low consequence and you have very low confidence in your own opinion, you should absolutely delegate. And delegate completely, let people make mistakes and learn. On the other side, obviously where the consequences are dramatic and you have extremely high conviction that you are right, you actually can’t let your junior colleague make a mistake.”
  • Peter Principle — “The selection of a candidate for a position is based on the candidate’s performance in their current role, rather than on abilities relevant to the intended role. Thus, employees only stop being promoted once they can no longer perform effectively, and ‘managers rise to the level of their incompetence.’


  • Metcalfe’s Law — “The value of a telecommunications network is proportional to the square of the number of connected users of the system…Within the context of social networks, many, including Metcalfe himself, have proposed modified models using (n × log n) proportionality rather than n^2 proportionality.”
  • Clarke’s Third Law — “Any sufficiently advanced technology is indistinguishable from magic.”


  • Cialdini’s Six Principles of Influence — Reciprocity (“People tend to return a favor.”), Commitment (“If people commit…they are more likely to honor that commitment.”), Social Proof (“People will do things they see other people are doing.”), Authority (“People will tend to obey authority figures.”), Liking (“People are easily persuaded by other people they like.”), and Scarcity (“Perceived scarcity will generate demand”). (related:foot-in-the-door technique)
  • Coda — “A term used in music primarily to designated a passage that brings a piece to an end.” (related: CTA.) People psychologically expect codas, and so they can be used for influence.


  • Strategy vs Tactics — Sun Tzu: “Strategy without tactics is the slowest route to victory. Tactics without strategy is the noise before defeat.”
  • Unknown Unknowns — “Known unknowns refers to ‘risks you are aware of, such as cancelled flights….’ Unknown unknowns are risks that ‘come from situations that are so out of this world that they never occur to you.’


  • Fighting the Last War — Using strategies and tactics that worked successfully in the past, but are no longer as useful.
  • Rumsfeld’s Rule — “You go to war with the Army you have. They’re not the Army you might want or wish to have at a later time.” (related: Joy’s law — “no matter who you are, most of the smartest people work for someone else.”)

Political Failure

  • Regulatory Capture — “When a regulatory agency, created to act in the public interest, instead advances the commercial or political concerns of special interest groups that dominate the industry or sector it is charged with regulating.” (related: Shirky principle — “Institutions will try to preserve the problem to which they are the solution.”)
  • Arrow’s Impossibility Theorem — “When voters have three or more distinct alternatives (options), no ranked order voting system can convert the ranked preferences of individuals into a community-wide (complete and transitive) ranking while also meeting a pre-specified set of criteria.” (related: approval voting)


  • Deliberate Practice — “How expert one becomes at a skill has more to do with how one practices than with merely performing a skill a large number of times.”
  • Dunning-Kruger Effect — “Relatively unskilled persons suffer illusory superiority, mistakenly assessing their ability to be much higher than it really is…[and] highly skilled individuals may underestimate their relative competence and may erroneously assume that tasks which are easy for them are also easy for others.” (related: overconfidence effect)


  • Focus on High-leverage Activities — “Leverage should be the central, guiding metric that helps you determine where to focus your time.” (related: Eisenhower decision matrix — “what is important is seldom urgent, and what is urgent is seldom important.”, “The best time to plant a tree was 20 years ago. The second best time is now.”, law of triviality — “members of an organisation give disproportionate weight to trivial issues.”)
  • Parkinson’s Law — “Work expands so as to fill the time available for its completion.”
  • Gate’s Law — “Most people overestimate what they can do in one year and underestimate what they can do in ten years.”
  • Makers vs Manager’s Schedule — “When you’re operating on the maker’s schedule, meetings are a disaster.” (related: Deep Work)


  • Consequentialism — “Holding that the consequences of one’s conduct are the ultimate basis for any judgment about the rightness or wrongness of that conduct.” (related: “ends justify the means”)
  • Distributive Justice vs Procedural Justice — “Procedural justice concerns the fairness and the transparency of the processes by which decisions are made, and may be contrasted with distributive justice (fairness in the distribution of rights or resources), and retributive justice (fairness in the punishment of wrongs).”
  • Agnosticism — “The view that the truth values of certain claims — especially metaphysical and religious claims such as whether God, the divine, or the supernatural exist — are unknown and perhaps unknowable.”

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