Browse Definitions:

Hofstadter's law

Contributor(s): Ivy Wigmore

Hofstadter’s law is the observation that “It always takes longer than you expect, even when you take into account Hofstadter's Law.” In other words, time estimates for how long anything will take to accomplish always fall short of the actual time required -- even when the time allotment is increased to compensate for the human tendency to underestimate it. The non-specificity of the reference (it) reflects that the law is broadly applicable in any situation where the task is complex. Hofstadter’s law is frequently evoked in IT contexts and is particularly relevant to time management, productivityproject management and software development.

Douglas Hofstadter, a cognitive scientist and author, introduced the law in his 1979  book Gödel, Escher, Bach: An Eternal Golden Braid. The system under discussion was chess-playing computers, which had been predicted to beat humans within 10 years. However, ten years after that prediction, humans were still winning. Hoftstadter wrote that the inablility for machines to triumph by that time was "just one more piece of evidence for the rather recursive Hofstadter's Law." (In fact, it wasn’t until 1996 that IBM’s Deep Blue computer beat the reigning world champion Garry Kasparov.)

Hofstadter’s law illustrates one element of optimism bias, which leads people to overestimate the benefits of some proposed system and underestimate the drawbacks, as well as the time required for completion. It’s also closely related to the ninety-ninety rule proposed by Tom Cargill of Bell Labs: The first 90 percent of the code accounts for the first 90 percent of the development time. The remaining 10 percent of the code accounts for the other 90 percent of the development time.

See a presentation on why everything takes longer than you think it will:

This was last updated in October 2016

Continue Reading About Hofstadter's law

Start the conversation

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.


Extensiones de Documento y Formatos de Documento

Accionado por:


  • risk map (risk heat map)

    A risk map, also known as a risk heat map, is a data visualization tool for communicating specific risks an organization faces. A...

  • internal audit (IA)

    An internal audit (IA) is an organizational initiative to monitor and analyze its own business operations in order to determine ...

  • pure risk (absolute risk)

    Pure risk, also called absolute risk, is a category of threat that is beyond human control and has only one possible outcome if ...


  • cloud ecosystem

    A cloud ecosystem is a complex system of interdependent components that all work together to enable cloud services.

  • cloud services

    Cloud services is an umbrella term that may refer to a variety of resources provided over the internet, or to professional ...

  • uncloud (de-cloud)

    The term uncloud describes the action or process of removing applications and data from a cloud computing platform.


  • federated identity management (FIM)

    Federated identity management (FIM) is an arrangement that can be made among multiple enterprises to let subscribers use the same...

  • cross-site scripting (XSS)

    Cross-site scripting (XSS) is a type of injection security attack in which an attacker injects data, such as a malicious script, ...

  • firewall

    In computing, a firewall is software or firmware that enforces a set of rules about what data packets will be allowed to enter or...




  • bad block

    A bad block is an area of storage media that is no longer reliable for storing and retrieving data because it has been physically...

  • all-flash array (AFA)

    An all-flash array (AFA), also known as a solid-state storage disk system, is an external storage array that uses only flash ...

  • volume manager

    A volume manager is software within an operating system (OS) that controls capacity allocation for storage arrays.


  • hybrid hard disk drive (HDD)

    A hybrid hard disk drive is an electromechanical spinning hard disk that contains some amount of NAND Flash memory.