Common Biases

From the article, Beyond Bias, strategy + business.

There are so many types of bias, or unconscious prejudice, that they’ve been classified. Here is a rundown of some common types of bias.

Do you recognize any of these?


Ingroup Bias: Perceiving people who are similar to you (in ethnicity, religion, socioeconomic status, profession, etc.) more positively. (“We can trust her; her hometown is near mine.”)

Outgroup Bias: Perceiving people who are different
from you more negatively. (“We can’t trust him; look where he grew up.”)


Belief Bias: Deciding whether an argument is strong or weak on the basis of whether you agree with its conclusion. (“This logic can’t be right; it would lead us to make that investment I don’t like.”)

Confirmation Bias: Seeking and finding evidence that confirms your beliefs and ignoring evidence that does not. (“I trust only one news channel; it tells the truth about the political party I despise.”)

Availability Bias: Making a decision based on the information that comes to mind most quickly, rather than on more objective evidence. (“I’m not worried about heart disease, but I live in fear of shark attacks because I saw one on the news.”)

Anchoring Bias: Relying heavily on the first piece of information offered (the “anchor”) when considering a decision. (“First they offered to sell the car for $35,000. Now they’re asking $30,000. It must be a good deal.”)

Base Rate Fallacy: When judging how probable something is, ignoring the base rate (the overall rate of occurrence). (“I know that only a small percentage of startups succeed, but ours is a sure thing.”)

Planning Fallacy: Underestimating how long it will take to complete a task, how much it will cost, and its risks, while overestimating its benefits. (“Trust me, we can finish this project in just three weeks.”)

Representativeness Bias: Believing that something that is more representative is necessarily more prevalent. (“There may be more qualified programmers in the rest of the world, but we’re staffing our software design group from Silicon Valley.”)

Hot Hand Fallacy: Believing that someone who was successful in the past has a greater chance of achieving further success. (“Bernard Madoff has had an unbroken winning streak; I’m reinvesting.”)

Halo Effect: Letting someone’s positive qualities in one area influence overall perception of that individual. (“He may not know much about people, but he’s a great engineer and a hard-working guy; let’s put him in charge of the team.”)


Blind Spot: Identifying biases in other people but not in yourself. (“She always judges people much too harshly.”)

False Consensus Effect: Overestimating the universality of your own beliefs, habits, and opinions. (“Of course I hate broccoli; doesn’t everyone?”)

Fundamental Attribution Error: Believing that your own errors or failures are due to external circumstances, but others’ errors are due to intrinsic factors like character. (“I made a mistake because I was having a bad day; you made a mistake because you’re not very smart.”)

Hindsight Bias: Seeing past events as having been predictable in retrospect. (“I knew the financial crisis was coming.”)

Illusion of Control: Overestimating your influence over external events. (“If I had just left the house a minute earlier, I wouldn’t have gotten stuck at this traffic light.”)

Illusion of Transparency: Overestimating the degree to which your mental state is accessible to others. (“Everyone in the room could see what I was thinking; I didn’t have to say it.”)

Egocentric Bias: Weighing information about yourself disproportionately in making judgments and decisions — for example, about communications strategy. (“There’s no need for a discussion of these legal issues; I understood them easily.”)


Endowment Effect: Expecting others to pay more for something than you would pay yourself. (“This is sure to fetch thousands at the auction.”)

Affective Forecasting: Judging your future emotional states based on how you feel now. (“I feel miserable about it, and I always will.”)

Temporal Discounting: Placing less value on rewards as they move further into the future. (“They made a great offer, but they can’t pay me for five weeks, so I’m going with someone else.”)


Loss Aversion: Making a risk-averse choice if the expected outcome is positive, but making a risk-seeking choice to avoid negative outcomes. (“We have to take a chance and invest in this, or our competitors will beat us to it.”)

Framing Effect: Basing a judgment on whether a decision is presented as a gain or as a loss, rather than on objective criteria. (“I hate this idea now that I see our competitors walking away from it.”)

Sunk Costs: Having a hard time giving up on something (a strategy, an employee, a process) after investing time, money, or training, even though the investment can’t be recovered. (“I’m not shutting this project down; we’d lose everything we’ve invested in it.”)

Published: July 12, 2016. Categories: Robert's Blog.