Prediction

Aprediction(Latinpræ-,"before," anddictum,"something said"^[1]) orforecastis a statement about afuture eventor about future data. Predictions are often, but not always, based upon experience or knowledge of forecasters. There is no universal agreement about the exact difference between "prediction" and "estimation";different authors and disciplines ascribe differentconnotations.

Future events are necessarilyuncertain,so guaranteed accurate information about the future is impossible. Prediction can be useful to assist in makingplansabout possible developments.

Opinion

In a non-statistical sense, the term "prediction" is often used to refer to aninformed guess or opinion.

A prediction of this kind might be informed by a predicting person'sabductive reasoning,inductive reasoning,deductive reasoning,andexperience;and may be useful—if the predicting person is aknowledgeable personin the field.^[2]

TheDelphi methodis a technique for eliciting such expert-judgement-based predictions in a controlled way. This type of prediction might be perceived as consistent with statistical techniques in the sense that, at minimum, the "data" being used is the predicting expert'scognitive experiencesforming anintuitive "probability curve."

Statistics

Instatistics,prediction is a part ofstatistical inference.One particular approach to such inference is known aspredictive inference,but the prediction can be undertaken within any of the several approaches to statistical inference. Indeed, one possible 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, which is not necessarily the same as prediction over time. When information is transferred across time, often to specific points in time, the process is known asforecasting.^[3]^{[failed verification]}Forecasting usually requirestime seriesmethods, while prediction is often performed oncross-sectional data.

Statistical techniques used for prediction includeregressionand its various sub-categories such aslinear regression,generalized linear models(logistic regression,Poisson regression,Probit regression), etc. In case of forecasting,autoregressive moving average modelsandvector autoregressionmodels can be utilized. When these and/or related, generalized set of regression ormachine learningmethods are deployed in commercial usage, the field is known aspredictive analytics.^[4]

In many applications, such as time series analysis, it is possible to estimate the models that generate the observations. If models can be expressed astransfer functionsor in terms of state-space parameters then smoothed, filtered and predicted data estimates can be calculated.^{[citation needed]}If the underlying generating models are linear then a minimum-varianceKalman filterand a minimum-variance smoother may be used to recover data of interest from noisy measurements. These techniques rely on one-step-ahead predictors (which minimise the variance of theprediction error). When the generating models are nonlinear then stepwise linearizations may be applied withinExtended Kalman Filterand smoother recursions. However, in nonlinear cases, optimum minimum-variance performance guarantees no longer apply.^[5]

To use regression analysis for prediction, data are collected on the variable that is to be predicted, called thedependent variableor response variable, and on one or more variables whose values arehypothesizedto influence it, calledindependent variablesor explanatory variables. Afunctional form,often linear, is hypothesized for the postulated causal relationship, and theparametersof the function areestimatedfrom the data—that is, are chosen so as to optimize is some way thefitof the function, thus parameterized, to the data. That is the estimation step. For the prediction step, explanatory variable values that are deemed relevant to future (or current but not yet observed) values of the dependent variable are input to the parameterized function to generate predictions for the dependent variable.^[6]

Science

NASA's 2004 predictions of the solar cycle, which were inaccurate (predicting thatsolar cycle 24would start in 2007 and be larger than cycle 23), and the refined predictions in 2012, showing it started in 2010 and is very small

In science, a prediction is a rigorous, often quantitative, statement, forecasting what would be observed under specific conditions; for example, according to theories ofgravity,if an apple fell from a tree it would be seen to move towards the center of the Earth with a specified and constantacceleration.Thescientific methodis built on testing statements that arelogical consequencesof scientific theories. This is done through repeatableexperimentsor observational studies.

Ascientific theorywhose predictions are contradicted by observations and evidence will be rejected. New theories that generate many new predictions can more easily be supported orfalsified(seepredictive power). Notions that make notestablepredictions are usually considered not to be part of science (protoscienceornescience) until testable predictions can be made.

Mathematical equationsandmodels,andcomputer models,are frequently used to describe the past and future behaviour of a process within the boundaries of that model. In some cases theprobabilityof an outcome, rather than a specific outcome, can be predicted, for example in much ofquantum physics.

Inmicroprocessors,branch predictionpermits avoidance ofpipelineemptying atbranch instructions.

Inengineering,possiblefailure modesare predicted and avoided by correcting thefailure mechanismcausing the failure.

Accurate prediction and forecasting are very difficult in some areas, such asnatural disasters,pandemics,demography,population dynamicsandmeteorology.^[7]For example, it is possible to predict the occurrence ofsolar cycles,but their exact timing and magnitude is much more difficult (see picture to right).

In materials engineering it is also possible to predict the life time of a material with a mathematical model.^[8]

Inmedicalscience predictive and prognosticbiomarkerscan be used to predict patient outcomes in response to various treatment or the probability of a clinical event.^[9]

Hypothesis

Established science makes useful predictions which are often extremely reliable and accurate; for example,eclipsesare routinely predicted.

New theories make predictions which allow them to be disproved by reality. For example, predicting the structure of crystals at the atomic level is a current research challenge.^[10]In the early 20th century the scientific consensus was that there existed an absoluteframe of reference,which was given the nameluminiferous ether.The existence of this absolute frame was deemed necessary for consistency with the established idea that the speed of light is constant. The famousMichelson–Morley experimentdemonstrated that predictions deduced from this concept were not borne out in reality, thus disproving the theory of an absolute frame of reference. Thespecial theory of relativitywas proposed by Einstein as an explanation for the seeming inconsistency between the constancy of the speed of light and the non-existence of a special, preferred or absolute frame of reference.

Albert Einstein's theory ofgeneral relativitycould not easily be tested as it did not produce any effects observable on a terrestrial scale. However, as one of the firsttests of general relativity,the theory predicted that large masses such asstarswould bend light, in contradiction to accepted theory; this was observed in a 1919 eclipse.

Medicine and healthcare

Predictive medicine

Predictive medicineis a field ofmedicinethat entails predicting theprobabilityofdiseaseand instituting preventive measures in order to either prevent the disease altogether or significantly decrease its impact upon the patient (such as by preventingmortalityor limitingmorbidity).^[11]

While different prediction methodologies exist, such asgenomics,proteomics,andcytomics,the most fundamental way to predict future disease is based on genetics. Although proteomics and cytomics allow for the early detection of disease, much of the time those detectbiological markersthat exist because a disease process hasalreadystarted. However, comprehensivegenetic testing(such as through the use ofDNA arraysorfull genome sequencing) allows for the estimation of disease risk years to decades before any disease even exists, or even whether a healthyfetusis at higher risk for developing a disease in adolescence or adulthood. Individuals who are more susceptible to disease in the future can be offered lifestyle advice or medication with the aim of preventing the predicted illness.

Current genetic testing guidelines supported by the health care professionals discourage purely predictive genetic testing of minors until they are competent to understand the relevancy of genetic screening so as to allow them to participate in the decision about whether or not it is appropriate for them.^[12]Genetic screeningof newborns and children in the field of predictive medicine is deemed appropriate if there is a compelling clinical reason to do so, such as the availability of prevention or treatment as a child that would prevent future disease.

Prognosis

Prognosis(Greek:πρόγνωσις "fore-knowing, foreseeing";pl.:prognoses) is amedicalterm for predicting the likelihood or expected development of a disease, including whether thesignsandsymptomswill improve or worsen (and how quickly) or remain stable over time; expectations of quality of life, such as the ability to carry out daily activities; the potential for complications and associated health issues; and the likelihood of survival (including life expectancy).^[13]^[14]A prognosis is made on the basis of the normal course of the diagnosed disease, the individual's physical and mental condition, the available treatments, and additional factors.^[14]A complete prognosis includes the expected duration, function, and description of the course of the disease, such as progressive decline, intermittent crisis, or sudden, unpredictable crisis.^[15]

When applied to largestatistical populations,prognostic estimates can be very accurate: for example the statement "45% of patients with severeseptic shockwill die within 28 days "can be made with some confidence, because previous research found that this proportion of patients died. This statistical information does not apply to the prognosis for each individual patient, because patient-specific factors can substantially change the expected course of the disease: additional information is needed to determine whether a patient belongs to the 45% who will die, or to the 55% who survive.^[16]

Clinical prediction rules

Aclinical prediction ruleor clinical probability assessment specifieshow to use medical signs,symptoms,and other findings to estimate the probability of a specific disease or clinical outcome.^[17]

Physicians have difficulty in estimated risks of diseases; frequently erring towards overestimation,^[18]perhaps due to cognitive biases such asbase rate fallacyin which the risk of an adverse outcome is exaggerated.

Finance

Mathematical models ofstock marketbehaviour (and economic behaviour in general) are also unreliable in predicting future behaviour. Among other reasons, this is because economic events may span several years, and the world is changing over a similar time frame, thus invalidating the relevance of past observations to the present. Thus there are an extremely small number (of the order of 1) of relevant past data points from which to project the future. In addition, it is generally believed that stock market prices already take into account all the information available to predict the future, and subsequent movements must therefore be the result of unforeseen events. Consequently, it is extremely difficult for astock investortoanticipateor predict astock market boom,or astock market crash.In contrast to predicting the actual stock return, forecasting of broadeconomic trendstends to have better accuracy. Such analysis is provided by both non-profit groups as well as by for-profit private institutions.^{[citation needed]}

Some correlation has been seen between actual stock market movements and prediction data from large groups in surveys and prediction games.

Anactuaryusesactuarial scienceto assess and predict future businessrisk,such that the risk(s) can bemitigated.For example, ininsurancean actuary would use alife table(which incorporates the historical experience of mortality rates and sometimes an estimate of future trends) to projectlife expectancy.

Sports

Predicting the outcome of sporting events is a business which has grown in popularity in recent years. Handicappers predict the outcome of games using a variety of mathematical formulas, simulation models orqualitative analysis.Early, well known sports bettors, such asJimmy the Greek,were believed to have access to information that gave them an edge. Information ranged from personal issues, such as gambling or drinking to undisclosed injuries; anything that may affect the performance of a player on the field.

Recent times have changed the way sports are predicted. Predictions now typically consist of two distinct approaches: Situational plays and statistical based models. Situational plays are much more difficult to measure because they usually involve the motivation of a team. Dan Gordon, noted handicapper, wrote "Without an emotional edge in a game in addition to value in a line, I won't put my money on it".^[19]These types of plays consist of: Betting on the home underdog, betting against Monday Night winners if they are a favorite next week, betting the underdog in "look ahead" games etc. As situational plays become more widely known they become less useful because they will impact the way the line is set.

The widespread use of technology has brought with it more modernsports betting systems.These systems are typically algorithms and simulation models based onregression analysis.Jeff Sagarin,a sports statistician, has brought attention to sports by having the results of his models published in USA Today. He is currently paid as a consultant by theDallas Mavericksfor his advice on lineups and the use of his Winval system, which evaluates free agents.Brian Burke,a formerNavyfighter pilot turned sports statistician, has published his results of using regression analysis to predict the outcome of NFL games.^[20]Ken Pomeroyis widely accepted as a leading authority on college basketball statistics. His website includes his College Basketball Ratings, a tempo based statistics system. Some statisticians have become very famous for having successful prediction systems. Dare wrote "the effective odds for sports betting and horse racing are a direct result of human decisions and can therefore potentially exhibit consistent error".^[21]Unlike other games offered in a casino, prediction in sporting events can be both logical and consistent.

Other more advance models include those based on Bayesian networks, which are causal probabilistic models commonly used for risk analysis and decision support. Based on this kind of mathematical modelling, Constantinou et al.,^[22]^[23]have developed models for predicting the outcome of association football matches.^[24]What makes these models interesting is that, apart from taking into consideration relevant historical data, they also incorporate all these vague subjective factors, like availability of key players, team fatigue, team motivation and so on. They provide the user with the ability to include their best guesses about things that there are no hard facts available. This additional information is then combined with historical facts to provide a revised prediction for future match outcomes. The initial results based on these modelling practices are encouraging since they have demonstrated consistent profitability against published market odds.

Nowadays sport betting is a huge business; there are many websites (systems) alongside betting sites, which give tips or predictions for future games.^[25]Some of these prediction websites (tipsters) are based on human predictions, but others on computer software sometimes called prediction robots or bots. Prediction bots can use different amount of data and algorithms and because of that their accuracy may vary.

Sites such asTzefimaintain that other sites' claim that they simulate the game 50,000 times before it is actually played on the field, is quite misleading and incorrect. This is due to the fact that those sites do not consider the human element of the game, and that abatterwith a.330ERAmaystrike outwhen the bases are loaded, or aquarterbackwith a 100+passer ratingmay throw aninterceptionat a crucial time. Tzefi boasts a 64.5% accuracy in predicting NFL games.

Social science

Prediction in the non-economic social sciences differs from the natural sciences and includes multiple alternative methods such as trend projection, forecasting, scenario-building and Delphi surveys. The oil company Shell is particularly well known for its scenario-building activities.^{[citation needed]}

One reason for the peculiarity of societal prediction is that in the social sciences, "predictors are part of the social context about which they are trying to make a prediction and may influence that context in the process".^[26]As a consequence, societal predictions can become self-destructing. For example, a forecast that a large percentage of a population will become HIV infected based on existing trends may cause more people to avoid risky behavior and thus reduce the HIV infection rate, invalidating the forecast (which might have remained correct if it had not been publicly known). Or, a prediction that cybersecurity will become a major issue may cause organizations to implement more security cybersecurity measures, thus limiting the issue.^[26]

Inpoliticsit is common to attempt to predict the outcome ofelectionsviapolitical forecastingtechniques (or assess the popularity ofpoliticians) through the use ofopinion polls.Prediction gameshave been used by many corporations and governments to learn about the most likely outcome of future events.

Prophecy

Predictions have often been made, from antiquity until the present, by usingparanormalorsupernaturalmeans such asprophecyor by observingomens.Methods includingwater divining,astrology,numerology,fortune telling,interpretation of dreams,and many other forms ofdivination,have been used for millennia to attempt to predict the future. These means of prediction have not been proven by scientific experiments.

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. Thebook of Revelation,in theNew Testament,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 asermonor other public forum.

Divinationis the attempt to gain insight into a question or situation by way of an occultic standardized process or ritual.^[27]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 querent should proceed by reading signs, events, oromens,or through alleged contact with asupernaturalagency, most often described as an angel or a god though viewed by Christians and Jews as a fallen angel or demon.^[28]

Fiction

Fiction (especially fantasy,forecastingand science fiction) often features instances of prediction achieved by unconventional means. Science fiction of the pastpredicted various modern technologies.

In fantasy literature, predictions are often obtained throughmagicorprophecy,sometimes referring back to old traditions. For example, inJ. R. R. Tolkien'sThe Lord of the Rings,many of the characters possess an awareness of events extending into the future, sometimes as prophecies, sometimes as more-or-less vague 'feelings'. The characterGaladriel,in addition, employs a water "mirror" to show images, sometimes of possible future events.

In some ofPhilip K. Dick's stories, mutant humans calledprecogscan foresee the future (ranging from days to years). In the story calledThe 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 afilmbySteven Spielbergin 2002.

In theFoundationseries byIsaac Asimov,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 ofpsychohistoryfounded upon his success can simulate history and extrapolate the present into the future.

InFrank Herbert's sequels to 1965'sDune,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 so-called "Golden Path"out of the trap.

InUrsula K. Le Guin'sThe Left Hand of Darkness,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.

Poetry

For the ancients, prediction, prophesy, and poetry were often intertwined.^[29]Prophecies were given in verse, and a word for poet in Latin is “vates” or prophet.^[29]Both poets and prophets claimed to be inspired by forces outside themselves. In contemporary cultures, theological revelation and poetry are typically seen as distinct and often even as opposed to each other. Yet the two still are often understood together as symbiotic in their origins, aims, and purposes.^[30]

Footnotes

^ "predict".Oxford English Dictionary(Online ed.).Oxford University Press.(Subscription orparticipating institution membershiprequired.)
^Silver, Nate(2012).The Signal and the Noise: Why so many predictions fail—but some don't.New York: Penguin Press.ISBN 978-1-59420-411-1.
^Cox, D. R. (2006).Principles of Statistical Inference.Cambridge University Press.ISBN 978-0-521-68567-2.
^Siegel, Eric (2013).Predictive Analysis: The Power to Predict Who Will Click, Buy, Lie, or Die.Hoboken, NJ: John Wiley & Sons.ISBN 978-1-118-35685-2.
^Julier, S. J.; Uhlmann, J. K. (2004). "Unscented filtering and nonlinear estimation".Proceedings of the IEEE.92(3): 401–422.CiteSeerX10.1.1.136.6539.doi:10.1109/jproc.2003.823141.S2CID 9614092.
^Fox, John (2016).Applied Regression Analysis and Generalized Linear Models(Third ed.). London: Sage.ISBN 978-1-4522-0566-3.
^Hendry, Andrew P (2023). "Prediction in ecology and evolution".BioScience.73(11): 785–799.doi:10.1093/biosci/biad083.
^Garcia Hernandez, Maria Inmaculada (2018). "Life time prediction for low energy and ecological effects bituminous mixtures".Construction and Building Materials.118:108–113.doi:10.1016/j.conbuildmat.2017.09.158.S2CID 139437088.
^Califf, R.M. (2018), "Biomarker definitions and their applications",Exp Biol Med,243(3): 213–221,doi:10.1177/1535370217750088,PMC5813875,PMID 29405771
^Woodley, S.M.; Catlow, R. (2008), "Crystal structure prediction from first principles",Nat Mater,7(12): 937–946,Bibcode:2008NatMa...7..937W,doi:10.1038/nmat2321,PMID 19029928
^"Predictive medicine: Genes indicate diseases before symptoms do".Archived fromthe originalon 2010-12-27.Retrieved2009-02-24.
^Borry P; Evers-Kiebooms G; Cornel MC; Clarke A; et al. (June 2009)."Genetic testing in asymptomatic minors: background considerations towards ESHG Recommendations".Eur. J. Hum. Genet.17(6): 711–9.doi:10.1038/ejhg.2009.25.PMC2947094.PMID 19277061.
^"What is the prognosis of a genetic condition?".Genetics Home Reference.NIH: U.S. National Library of Medicine.Retrieved2018-05-20.
^^a ^b"Prognosis".Nature Publishing Group.Retrieved20 May2018.
^Hansebout, R. R.; Cornacchi, S. D.; Haines, T.; Goldsmith, C. H. (2009)."How to use an article about prognosis".Canadian Journal of Surgery. Journal Canadien de Chirurgie.52(4): 328–336.PMC2724829.PMID 19680521.
^Gould, Stephen Jay (2013),"The Median Isn't the Message",AMA Journal of Ethics,15(1): 77–81,doi:10.1001/virtualmentor.2013.15.1.mnar1-1301,PMID 23356812
^McGinn TG, Guyatt GH, Wyer PC, Naylor CD, Stiell IG, Richardson WS (2000). "Users' guides to the medical literature: XXII: how to use articles about clinical decision rules. Evidence-Based Medicine Working Group".JAMA.284(1): 79–84.doi:10.1001/jama.284.1.79.PMID 10872017.
^Friedmann PD, Brett AS, Mayo-Smith MF (1996). "Differences in generalists' and cardiologists' perceptions of cardiovascular risk and the outcomes of preventive therapy in cardiovascular disease".Ann. Intern. Med.124(4): 414–21.doi:10.7326/0003-4819-124-4-199602150-00005.PMID 8554250.S2CID 25470460.
^Gordon, Dan (2005).Beat the Sports Books.New York, United States: Cardoza.ISBN 978-1-5804-2174-4.
^Burke, Brian (2008)."NFL Win Prediction Methodology".
^Dare, William H (2006).Risk Return and Gambling Market Efficiency(PDF).Oklahoma City, United States: Oklahoma State University.
^Constantinou, Anthony; Fenton, N.; Neil, M. (2012)."pi-football: A Bayesian network model for forecasting Association Football match outcomes"(PDF).Knowledge-Based Systems.36:322–339.CiteSeerX10.1.1.420.4110.doi:10.1016/j.knosys.2012.07.008.
^Constantinou, Anthony; Fenton, N.; Neil, M. (2013)."Profiting from an inefficient Association Football gambling market: Prediction, Risk and Uncertainty using Bayesian networks".Knowledge-Based Systems.50:60–86.doi:10.1016/j.knosys.2013.05.008.
^Patel, Mahesh (24 Jan 2023)."Football prediction".Lootrs.Retrieved24 Jan2023.
^"Soccer picks and predictions".Soccer Punt.
^^a ^bOverland, Indra (2019-03-01)."The geopolitics of renewable energy: Debunking four emerging myths".Energy Research & Social Science.49:36–40.Bibcode:2019ERSS...49...36O.doi:10.1016/j.erss.2018.10.018.hdl:11250/2579292.ISSN 2214-6296.
^Peek, P.M.African Divination Systems: Ways of Knowing.page 2. Indiana University Press. 1991.
^Definition of divination
^^a ^bStallings, A. E.(2020-08-22)."Poetry and Prophecy".Poetry Foundation.Retrieved2020-08-22.
^Franke, William (2016-05-09)."Poetry, Prophecy, and Theological Revelation".Oxford Research Encyclopedia of Religion.doi:10.1093/acrefore/9780199340378.013.205.ISBN 9780199340378.Retrieved2020-08-22.