A
prediction or
forecastForecasting is the process of making statements about events whose actual outcomes have not yet been observed. A commonplace example might be estimation for some variable of interest at some specified future date. Prediction is a similar, but more general term...
is a statement about the way things will happen in the
futureThe future is the indefinite time period after the present. Its arrival is considered inevitable due to the existence of time and the laws of physics. Due to the nature of the reality and the unavoidability of the future, everything that currently exists and will exist is temporary and will come...
, often but not always based on experience or knowledge. While there is much overlap between
prediction and
forecast, a
prediction may be a statement that some outcome is expected, while a
forecast may cover a range of possible outcomes.
Although guaranteed information about the information is in many cases impossible, prediction is necessary to allow
plansPlanning in organizations and public policy is both the organizational process of creating and maintaining a plan; and the psychological process of thinking about the activities required to create a desired goal on some scale. As such, it is a fundamental property of intelligent behavior...
to be made about possible developments; Howard H. Stevenson writes that prediction in business "... is at least two things: Important and hard."
Prediction is closely related to uncertainty.
Reference class forecastingReference class forecasting is the method of predicting the future, through looking at similar past situations and their outcomes.Reference class forcasting predicts the outcome of a planned action based on actual outcomes in a reference class of similar actions to that being forecast. The theories...
was developed to eliminate or reduce uncertainty in prediction.
The
etymologyEtymology is the study of the history of words, their origins, and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during...
of
prediction is
LatinLatin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
(
præ-, "before," and
dicere, "to say").
Informal prediction from hypothesis
Outside the rigorous context of science, prediction is often confused with
informed guess or opinionA hypothesis is a proposed explanation for a phenomenon. The term derives from the Greek, ὑποτιθέναι – hypotithenai meaning "to put under" or "to suppose". For a hypothesis to be put forward as a scientific hypothesis, the scientific method requires that one can test it...
.
A prediction of this kind might be
(inductively)Inductive reasoning, also known as induction or inductive logic, is a kind of reasoning that constructs or evaluates propositions that are abstractions of observations. It is commonly construed as a form of reasoning that makes generalizations based on individual instances...
validIn logic, argument is valid if and only if its conclusion is entailed by its premises, a formula is valid if and only if it is true under every interpretation, and an argument form is valid if and only if every argument of that logical form is valid....
if the predictor is a
knowledgeable personThe word Authority is derived mainly from the Latin word auctoritas, meaning invention, advice, opinion, influence, or command. In English, the word 'authority' can be used to mean power given by the state or by academic knowledge of an area .-Authority in Philosophy:In...
in the field and is employing
sound reasoningIn mathematical logic, a logical system has the soundness property if and only if its inference rules prove only formulas that are valid with respect to its semantics. In most cases, this comes down to its rules having the property of preserving truth, but this is not the case in general. The word...
and
accurateIn the fields of science, engineering, industry and statistics, the accuracy of a measurement system is the degree of closeness of measurements of a quantity to that quantity's actual value. The precision of a measurement system, also called reproducibility or repeatability, is the degree to which...
dataMeasurement is the process or the result of determining the ratio of a physical quantity, such as a length, time, temperature etc., to a unit of measurement, such as the metre, second or degree Celsius...
. Large corporations invest heavily in this kind of activity to help focus attention on possible events, risks and business opportunities, using
futuristsFuturists or futurologists are scientists and social scientists whose speciality is to attempt to systematically predict the future, whether that of human society in particular or of life on earth in general....
. Such work brings together all available past and current data, as a basis to develop reasonable expectations about the future.
Opinion polls
In
politicsPolitics is a process by which groups of people make collective decisions. The term is generally applied to the art or science of running governmental or state affairs, including behavior within civil governments, but also applies to institutions, fields, and special interest groups such as the...
it is common to attempt to predict the outcome of elections via
political forecastingPolitical forecasting aims at predicting the outcome of elections. Models include:- Opinion polls :Polls are an integral part of political forecasting. However, incorporating poll results into political forecasting models can cause problems in predicting the outcome of elections...
techniques (or assess the popularity of politicians) through the use of opinion polls.
Prediction gamesA prediction game is a game which allow users to guess at the outcome of future events. Prediction games are generally operated online and are free for users to play...
have been used by many corporations and governments to learn about the most likely outcome of future events.
Statistics
In
statisticsStatistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....
, prediction is a part of
statistical inferenceIn statistics, statistical inference is the process of drawing conclusions from data that are subject to random variation, for example, observational errors or sampling variation...
. One particular approach to such inference is known as
predictive inferencePredictive inference is an approach to statistical inference that emphasizes the prediction of future observations based on past observations.Initially, predictive inference was based on observable parameters and it was the main purpose of studying probability, but it fell out of favor in the 20th...
, but the prediction can be undertaken within any of the several appoaches to statistical inference. Indeed, one description of statistics is that it provides a means of transferring knowledge about a sample of a population to the whole population, and to other related populations. When information is transferred across time, often to specific points in time, the process is known as
forecastingForecasting is the process of making statements about events whose actual outcomes have not yet been observed. A commonplace example might be estimation for some variable of interest at some specified future date. Prediction is a similar, but more general term...
.
Supernatural (prophecy)
Main article: ProphecyProphecy is a process in which one or more messages that have been communicated to a prophet are then communicated to others. Such messages typically involve divine inspiration, interpretation, or revelation of conditioned events to come as well as testimonies or repeated revelations that the...
Predictions have often been made, from antiquity until the present, by using
paranormalParanormal is a general term that designates experiences that lie outside "the range of normal experience or scientific explanation" or that indicates phenomena understood to be outside of science's current ability to explain or measure...
or
supernaturalThe supernatural or is that which is not subject to the laws of nature, or more figuratively, that which is said to exist above and beyond nature...
means such as
prophecyProphecy is a process in which one or more messages that have been communicated to a prophet are then communicated to others. Such messages typically involve divine inspiration, interpretation, or revelation of conditioned events to come as well as testimonies or repeated revelations that the...
or by observing
omenAn omen is a phenomenon that is believed to foretell the future, often signifying the advent of change...
s. Methods including water divining,
astrologyAstrology consists of a number of belief systems which hold that there is a relationship between astronomical phenomena and events in the human world...
,
numerologyNumerology is any study of the purported mystical relationship between a count or measurement and life. It has many systems and traditions and beliefs...
, fortune telling,
interpretation of dreamsInterpretation of dreams may refer to:* Dream interpretation is the process of assigning meaning to dreams* Oneiromancy, a form of divination based upon dreams* The Interpretation of Dreams, Sigmund Freud's 1899 book about psychoanalysis and dreams...
, and many other forms of
divinationDivination is the attempt to gain insight into a question or situation by way of an occultic standardized process or ritual...
, have been used for millennia to attempt to predict the future. These means of prediction have not been substantiated by controlled experiments, and are disputed by most, including scientists and skeptics.
Prediction in science
In science a prediction is a rigorous, often quantitative, statement, forecasting what will happen under specific conditions; for example, if an apple falls from a tree it will be attracted towards the center of the earth by gravity with a specified and constant
accelerationIn physics, acceleration is the rate of change of velocity with time. In one dimension, acceleration is the rate at which something speeds up or slows down. However, since velocity is a vector, acceleration describes the rate of change of both the magnitude and the direction of velocity. ...
. The
scientific methodScientific method refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering empirical and measurable evidence subject to specific principles of...
is built on testing assertions that are logical consequences of scientific theories. This is done through repeatable experiments or observational studies.
A
scientific theoryA scientific theory comprises a collection of concepts, including abstractions of observable phenomena expressed as quantifiable properties, together with rules that express relationships between observations of such concepts...
whose assertions are contradicted by observations and evidence will be rejected. Notions that make no
testable predictions are usually considered not to be part of science (
protoscienceIn the philosophy of science, a protoscience is an area of scientific endeavor that is in the process of becoming established. Protoscience is distinguished from pseudoscience by its standard practices of good science, such as a willingness to be disproven by new evidence, or to be replaced by a...
or nescience) until testable predictions can be made.
New theories that generate many new predictions can more easily be supported or
falsifiedFalsifiability or refutability of an assertion, hypothesis or theory is the logical possibility that it can be contradicted by an observation or the outcome of a physical experiment...
(see
predictive powerThe predictive power of a scientific theory refers to its ability to generate testable predictions. Theories with strong predictive power are highly valued, because the predictions can often encourage the falsification of the theory...
).
In some cases the
probabilityProbability is ordinarily used to describe an attitude of mind towards some proposition of whose truth we arenot certain. The proposition of interest is usually of the form "Will a specific event occur?" The attitude of mind is of the form "How certain are we that the event will occur?" The...
of an outcome, rather than a specific outcome, can be predicted, for example in much of quantum physics.
Mathematical equations and
modelsA mathematical model is a description of a system using mathematical concepts and language. The process of developing a mathematical model is termed mathematical modeling. Mathematical models are used not only in the natural sciences and engineering disciplines A mathematical model is a...
, and computer models, are frequently used to describe the past and future behaviour of something.
In
microprocessorA microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
s,
branch predictionIn computer architecture, a branch predictor is a digital circuit that tries to guess which way a branch will go before this is known for sure. The purpose of the branch predictor is to improve the flow in the instruction pipeline...
permits avoidance of pipeline emptying at
branch instructionsA branch is sequence of code in a computer program which is conditionally executed depending on whether the flow of control is altered or not . The term can be used when referring to programs in high level languages as well as program written in machine code or assembly language...
. In
engineeringEngineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
, possible failure modes are predicted and avoided by correcting the mechanism causing the failure.
Accurate prediction and forecasting are very difficult in some areas, such as software reliability, natural disasters, pandemics,
demographyDemography is the statistical study of human population. It can be a very general science that can be applied to any kind of dynamic human population, that is, one that changes over time or space...
,
population dynamicsPopulation dynamics is the branch of life sciences that studies short-term and long-term changes in the size and age composition of populations, and the biological and environmental processes influencing those changes...
and
meteorologyMeteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...
.
Scientific hypothesis and prediction
Established science makes useful predictions which are considered to be extremely reliable and accurate; for example,
eclipseAn eclipse is an astronomical event that occurs when an astronomical object is temporarily obscured, either by passing into the shadow of another body or by having another body pass between it and the viewer...
s are routinely predicted.
New theories make predictions which allow them to be falsified if the predictions are not borne out. For example in the early twentieth century the scientific consensus was that there was an absolute
frame of referenceA frame of reference in physics, may refer to a coordinate system or set of axes within which to measure the position, orientation, and other properties of objects in it, or it may refer to an observational reference frame tied to the state of motion of an observer.It may also refer to both an...
, given the name
luminiferous ether. The famous
Michelson-Morley experimentThe Michelson–Morley experiment was performed in 1887 by Albert Michelson and Edward Morley at what is now Case Western Reserve University in Cleveland, Ohio. Its results are generally considered to be the first strong evidence against the theory of a luminiferous ether and in favor of special...
ruled this out, falsifying the idea of an absolute frame and leaving the very counter-intuitive special theory of relativity as the only possibility.
Albert EinsteinAlbert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...
's theory of
general relativityGeneral relativity or the general theory of relativity is the geometric theory of gravitation published by Albert Einstein in 1916. It is the current description of gravitation in modern physics...
could not easily be tested as it did not produce any effects observable on a terrestrial scale. However, the theory predicted that large masses such as
starA star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s would bend light, in contradiction to accepted theory; this was observed in a 1919 eclipse.
Finance
Mathematical models of
stock marketA stock market or equity market is a public entity for the trading of company stock and derivatives at an agreed price; these are securities listed on a stock exchange as well as those only traded privately.The size of the world stock market was estimated at about $36.6 trillion...
behaviour are also unreliable in predicting future behaviour. Consequently, stock investors may
anticipateForesight or forethought may refer to:* Foresight , ability to predict or plan for the future* Foresight , management planning principle* Foresight , European planning mechanism for public policy...
or predict a stock market boom, or fail to anticipate or predict a
stock market crashA stock market crash is a sudden dramatic decline of stock prices across a significant cross-section of a stock market, resulting in a significant loss of paper wealth. Crashes are driven by panic as much as by underlying economic factors...
.
Some correlation has been seen between actual stock market movements and prediction data from large groups in surveys and prediction games.
An
actuaryAn actuary is a business professional who deals with the financial impact of risk and uncertainty. Actuaries provide expert assessments of financial security systems, with a focus on their complexity, their mathematics, and their mechanisms ....
uses
actuarial scienceActuarial science is the discipline that applies mathematical and statistical methods to assess risk in the insurance and finance industries. Actuaries are professionals who are qualified in this field through education and experience...
to assess and predict future business
riskRisk is the potential that a chosen action or activity will lead to a loss . The notion implies that a choice having an influence on the outcome exists . Potential losses themselves may also be called "risks"...
, such that the risk(s) can be
mitigatedEmergency management is the generic name of an interdisciplinary field dealing with the strategic organizational management processes used to protect critical assets of an organization from hazard risks that can cause events like disasters or catastrophes and to ensure the continuance of the...
.
For example, in
insuranceIn law and economics, insurance is a form of risk management primarily used to hedge against the risk of a contingent, uncertain loss. Insurance is defined as the equitable transfer of the risk of a loss, from one entity to another, in exchange for payment. An insurer is a company selling the...
an actuary would use a life table to predict (truly, estimate or compute)
life expectancyLife expectancy is the expected number of years of life remaining at a given age. It is denoted by ex, which means the average number of subsequent years of life for someone now aged x, according to a particular mortality experience...
.
Vision and prophecy
In literature, vision and prophecy are literary devices used to present a possible timeline of future events. They can be distinguished by vision referring to what an individual sees happen. The
New TestamentThe New Testament is the second major division of the Christian biblical canon, the first such division being the much longer Old Testament....
book of
Revelation (Bible)In religion and theology, revelation is the revealing or disclosing, through active or passive communication with a supernatural or a divine entity...
thus uses vision as a literary device in this regard. It is also prophecy or prophetic literature when it is related by an individual in a
sermonA sermon is an oration by a prophet or member of the clergy. Sermons address a Biblical, theological, religious, or moral topic, usually expounding on a type of belief, law or behavior within both past and present contexts...
or other public forum.
DivinationDivination is the attempt to gain insight into a question or situation by way of an occultic standardized process or ritual...
is the attempt to gain insight into a question or situation by way of an occultic standardized process or ritual. It is an integral part of witchcraft and has been used in various forms for thousands of years. Diviners ascertain their interpretations of how a
querentQuerent as "one who seeks" is derived, according to the Oxford English Dictionary, from the Latin quærēns "seeker," the present participle of quærere "to seek, gain, ask."...
should proceed by reading signs, events, or
omenAn omen is a phenomenon that is believed to foretell the future, often signifying the advent of change...
s, or through alleged contact with a
supernaturalThe supernatural or is that which is not subject to the laws of nature, or more figuratively, that which is said to exist above and beyond nature...
agency, most often describe as an angel or a god though viewed by Christians and Jews as a fallen angel or demon.
Prediction in fiction
Fiction (especially fantasy,
forecastingA future history is a postulated history of the future and is used by authors in the subgenre of speculative fiction to construct a common background for fiction...
and science fiction) often features instances of prediction achieved by unconventional means.
- In fantasy literature, predictions are often obtained through magic
Magic is the claimed art of manipulating aspects of reality either by supernatural means or through knowledge of occult laws unknown to science. It is in contrast to science, in that science does not accept anything not subject to either direct or indirect observation, and subject to logical...
or prophecyProphecy is a process in which one or more messages that have been communicated to a prophet are then communicated to others. Such messages typically involve divine inspiration, interpretation, or revelation of conditioned events to come as well as testimonies or repeated revelations that the...
, sometimes referring back to old traditions. For example, in J. R. R. TolkienJohn Ronald Reuel Tolkien, CBE was an English writer, poet, philologist, and university professor, best known as the author of the classic high fantasy works The Hobbit, The Lord of the Rings, and The Silmarillion.Tolkien was Rawlinson and Bosworth Professor of Anglo-Saxon at Pembroke College,...
's The Lord of the RingsThe Lord of the Rings is a high fantasy epic written by English philologist and University of Oxford professor J. R. R. Tolkien. The story began as a sequel to Tolkien's earlier, less complex children's fantasy novel The Hobbit , but eventually developed into a much larger work. It was written in...
, many of the characters possess an awareness of events extending into the future, sometimes as prophecies, sometimes as more-or-less vague 'feelings'. The character GaladrielGaladriel is a character created by J.R.R. Tolkien, appearing in his Middle-earth legendarium. She appears in The Lord of the Rings, The Silmarillion, and Unfinished Tales....
, in addition, employs a water "mirror" to show images, sometimes of possible future events.
- In some of Philip K. Dick
Philip Kindred Dick was an American novelist, short story writer and essayist whose published work is almost entirely in the science fiction genre. Dick explored sociological, political and metaphysical themes in novels dominated by monopolistic corporations, authoritarian governments and altered...
's stories, mutant humans called precogs can foresee the future (ranging from days to years). In the story called The Golden Man, an exceptional mutant can predict the future to an indefinite range (presumably up to his death), and thus becomes completely non-human, an animal that follows the predicted paths automatically. Precogs also play an essential role in another of Dick's stories, The Minority Report, which was turned into a filmMinority Report is a 2002 American neo-noir science fiction film directed by Steven Spielberg and loosely based on the short story "The Minority Report" by Philip K. Dick. It is set primarily in Washington, D.C...
by Steven SpielbergSteven Allan Spielberg KBE is an American film director, screenwriter, producer, video game designer, and studio entrepreneur. In a career of more than four decades, Spielberg's films have covered many themes and genres. Spielberg's early science-fiction and adventure films were seen as an...
in 2002.
- In the Foundation series by Isaac Asimov
Isaac Asimov was an American author and professor of biochemistry at Boston University, best known for his works of science fiction and for his popular science books. Asimov was one of the most prolific writers of all time, having written or edited more than 500 books and an estimated 90,000...
, a mathematician finds out that historical events (up to some detail) can be theoretically modelled using equations, and then spends years trying to put the theory in practice. The new science of psychohistoryPsychohistory is a fictional science in Isaac Asimov's Foundation universe which combines history, sociology, and mathematical statistics to make general predictions about the future behavior of very large groups of people, such as the Galactic Empire...
founded upon his success can simulate history and extrapolate the present into the future.
- In Frank Herbert
Franklin Patrick Herbert, Jr. was a critically acclaimed and commercially successful American science fiction author. Although a short story author, he is best known for his novels, most notably Dune and its five sequels...
's sequels to DuneDune is a science fiction novel written by Frank Herbert, published in 1965. It won the Hugo Award in 1966, and the inaugural Nebula Award for Best Novel...
, his characters are dealing with the repercussions of being able to see the possible futures and select amongst them. Herbert sees this as a trap of stagnation, and his characters follow a Golden Path out of the trap.
- In Ursula K. Le Guin
Ursula Kroeber Le Guin is an American author. She has written novels, poetry, children's books, essays, and short stories, notably in fantasy and science fiction...
's The Left Hand of DarknessThe Left Hand of Darkness is a 1969 science fiction novel by Ursula K. Le Guin. It is part of the Hainish Cycle, a series of books by Le Guin all set in the fictional Hainish universe....
, the humanoid inhabitants of planet Gethen have mastered the art of prophecy and routinely produce data on past, present or future events on request. In this story, this was a minor plot device.
See also
- Astrology
Astrology consists of a number of belief systems which hold that there is a relationship between astronomical phenomena and events in the human world...
- Consensus forecasts
In a number of sciences, ranging from econometrics to meteorology, consensus forecasts are predictions of the future that are created by combining together several separate forecasts which have often been created using different methodologies...
- Delphi method
The Delphi method is a structured communication technique, originally developed as a systematic, interactive forecasting method which relies on a panel of experts.In the standard version, the experts answer questionnaires in two or more rounds...
- Egain Forecasting
Egain forecasting is a method of controlling building heating by calculating demand for heating energy that should be supplied to the building in each time unit. By combining physics of structures with meteorology, properties of the building, weather conditions including outdoor temperature, wind...
- Forecasting
Forecasting is the process of making statements about events whose actual outcomes have not yet been observed. A commonplace example might be estimation for some variable of interest at some specified future date. Prediction is a similar, but more general term...
- Famous predictions
There have been various notable predictions made throughout history, including those by scientists based on the scientific method, theoretical non-fiction predictions of social and technological change of futurologists, economic forecasts of economists regarding financial markets, wealth and...
- Futures Studies
- Optimism bias
Optimism bias is the demonstrated systematic tendency for people to be overly optimistic about the outcome of planned actions. This includes over-estimating the likelihood of positive events and under-estimating the likelihood of negative events. Along with the illusion of control and illusory...
- Predictability
Predictability is the degree to which a correct prediction or forecast of a system's state can be made either qualitatively or quantitatively.-Predictability and Causality:...
- Prediction interval
In statistical inference, specifically predictive inference, a prediction interval is an estimate of an interval in which future observations will fall, with a certain probability, given what has already been observed...
- Prediction market
Prediction markets are speculative markets created for the purpose of making predictions...
- Predictions of Soviet collapse
There were people who predicted that the Soviet Union would eventually be dissolved before the process of dissolution began with the fall of the Berlin Wall in November 1989....
- Predictive medicine
Predictive medicine is a rapidly emerging field of medicine that entails predicting disease and instituting preventive measures in order to either prevent the disease altogether or significantly decrease its impact upon the patient...
- Reference class forecasting
Reference class forecasting is the method of predicting the future, through looking at similar past situations and their outcomes.Reference class forcasting predicts the outcome of a planned action based on actual outcomes in a reference class of similar actions to that being forecast. The theories...
- Regression analysis
In statistics, regression analysis includes many techniques for modeling and analyzing several variables, when the focus is on the relationship between a dependent variable and one or more independent variables...
- Thought experiment
A thought experiment or Gedankenexperiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences...
- Traffic forecasting
- Trend estimation
Trend estimation is a statistical technique to aid interpretation of data. When a series of measurements of a process are treated as a time series, trend estimation can be used to make and justify statements about tendencies in the data...
- Weather forecasting
Weather forecasting is the application of science and technology to predict the state of the atmosphere for a given location. Human beings have attempted to predict the weather informally for millennia, and formally since the nineteenth century...
External links