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One catalogue of research methods — learn how each one works, when to use it, and what it can’t do.

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FieldHealth & Medicine716Psychology570Business & Finance410Engineering330Life Sciences263Education261Research Practice248
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Entries are compiled from published sources for reference. Verifying the accuracy and suitability of any information for your own use remains your responsibility.

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Natural Sciences236
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MethodStatistics1,836AI & ML1,661Decision Sciences932Research Methods1,354Measurement1,745Causal & Evidence532Research Practice118
1,836 methods · StatisticsClear
Real methods matching your filter.
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urban studies

15-Minute City Analysis

15-minute city analysis assesses how many of life's daily needs — shops, schools, healthcare, work, recreation — residents can reach within a short walk or bike ride, typically fifteen minutes, from their homes. Articulated by Carlos Moreno in 2021 under the banner of chrono-urbanism, the concept reorients planning aro

1 source2021
econometrics

2SLS Regression

Two-Stage Least Squares is a two-step instrumental-variables estimator that addresses endogeneity, the situation where a regressor is correlated with the error term. In the first stage the endogenous regressor is predicted from instrumental variables, and in the second stage the structural equation is estimated using t

1 source2009
experimental design

A/B Test

An A/B test is a randomized controlled experiment that simultaneously exposes two groups of users to a control variant (A) and a treatment variant (B) in order to determine whether a measured outcome differs significantly between them. The modern online controlled experiment framework was systematized by Ron Kohavi and

2 sources1935
social epidemiology

Abridged Life Table

The abridged life table is the workhorse of demography and population health for summarizing the mortality experience of a population in a single, age-grouped table. Instead of a single-year (complete) life table, it works on broad age intervals — typically <1, 1-4, then five-year groups up to an open-ended oldest inte

2 sources1984
survival

Accelerated Failure Time Model

The Accelerated Failure Time model is a parametric regression approach to survival analysis — formally reviewed and advocated by L. J. Wei in 1992 — in which covariates act as multiplicative factors that directly stretch or compress the time-to-event scale. Unlike the Cox proportional-hazards model, which models how co

3 sources1992
sport leisure studies

Accelerometer Cut-Point Calibration

Accelerometer cut-point calibration solves the central translation problem of objective physical-activity measurement: a wearable accelerometer outputs dimensionless 'counts,' but researchers and health guidelines speak in intensities — sedentary, light, moderate, vigorous. Calibration establishes the count thresholds

2 sources1998
human geography

Accessibility Analysis

Accessibility analysis measures how easily opportunities — jobs, shops, clinics, parks — can be reached from a given location, combining the attractiveness (size) of destinations with the cost of travelling to them. The gravity-based formulation introduced by Walter Hansen in 1959 sums the opportunities at all destinat

2 sources1959
urban studies

Accessibility Equity Analysis

Accessibility equity analysis asks not just how much access to opportunities a place has, but how that access is distributed across people and social groups — who can reach jobs, healthcare, and education, and who is left behind. It pairs an accessibility measure, in the tradition formalized by Karst Geurs and Bert van

1 source2004
machine learning

Active learning Gaussian process

Active Learning Gaussian Process (GP-AL) combines a Gaussian process probabilistic model with an active learning query strategy, using the GP's posterior uncertainty to select the most informative unlabeled examples for labeling. This iterative approach minimizes labeling effort while maximizing predictive accuracy, ma

2 sources1992
machine learning

Active Learning Logistic Regression

Active Learning with Logistic Regression is an iterative label-efficient framework in which a logistic regression model selects the unlabeled examples it is most uncertain about, an oracle (human annotator) labels them, and the model is retrained — repeating until a labeling budget or accuracy target is met. It dramati

2 sources1994
social gerontology

Active Life Expectancy Estimation

Active life expectancy (ALE) estimates how many of an older person's remaining years are expected to be lived in an active, independent state — free of disability in basic activities of daily living — as opposed to a dependent state requiring help. Introduced by Sidney Katz, Laurence Branch, and colleagues in 1983 in t

1 source1983
social psychology

Actor-Partner Interdependence Model

The Actor-Partner Interdependence Model (APIM), formalized by Kenny, Kashy, and Cook, is the standard framework for analyzing dyadic data in which two people's outcomes depend on both their own and their partner's characteristics. For each member of a dyad, the model estimates an actor effect -- the influence of a pers

1 source2006
experimental design

Adaptive A/B test

An Adaptive A/B test is an experimental design that dynamically reallocates traffic or participants toward better-performing variants during the experiment itself, rather than holding allocations fixed until the end. Drawing on multi-armed bandit algorithms such as Thompson Sampling or Upper Confidence Bound (UCB), it

2 sources1952
epidemiology

Adaptive Competing Risks Analysis

Adaptive competing risks analysis combines the Fine-Gray subdistribution hazard framework — which models the cumulative incidence of one cause of failure in the presence of other mutually exclusive causes — with adaptive or group-sequential interim monitoring rules. This allows a clinical trial or observational study t

2 sources1999
epidemiology

Adaptive Cox Proportional Hazards

The Adaptive Cox Proportional Hazards model extends the classic Cox regression for time-to-event outcomes by adding adaptive LASSO (or related) penalization. It simultaneously estimates hazard ratios and performs variable selection, shrinking irrelevant covariate coefficients exactly to zero. This makes it especially v

2 sources2007
statistics

Adjusted Boxplot

The Adjusted Boxplot is a robust descriptive tool introduced by Hubert and Vandervieren (2008) that corrects the classical IQR-based boxplot for skewness using the medcouple statistic, reducing the false labelling of outliers in asymmetric data.

1 source2008
criminology

Age-Crime Curve Modeling

Age-crime curve modeling fits statistical functions to the well-known relationship between age and offending: crime rises sharply in adolescence, peaks in the late teens or early twenties, and declines through adulthood. Brought to prominence by Hirschi and Gottfredson's 1983 claim that this curve is invariant, and ela

2 sources1983
social epidemiology

Age-Period-Cohort Analysis

Age-period-cohort (APC) analysis decomposes variation in disease or mortality rates into three temporal components: the effect of age (biological and accumulated risk), the effect of period (influences hitting everyone alive at a given calendar time, such as a new treatment or a recession), and the effect of cohort (la

2 sources1983
demography

Age-Period-Cohort Model

The age-period-cohort (APC) model decomposes variation in a vital rate — mortality, incidence, fertility — into three temporal dimensions: the age of individuals, the calendar period of observation, and the birth cohort to which they belong. It is the standard framework for asking whether a trend reflects how risk chan

2 sources1983
historical demography

Aggregative Parish Register Analysis

Aggregative parish register analysis is the foundational technique of English historical demography, compiling the simple monthly and annual counts of baptisms, marriages and burials recorded in parish registers into continuous long-run series. Unlike family reconstitution, it does not identify individuals; it treats t

2 sources1981
food agriculture studies

Agricultural Household Model

The agricultural household model treats the farm household as a single unit that is simultaneously a producer and a consumer, choosing how much to grow, how much labour to hire or supply, and how much to consume — decisions that ordinary firm theory and consumer theory treat as separate. Synthesised in Singh, Squire, a

2 sources1986
food agriculture studies

Agricultural Market Integration Analysis

Agricultural market integration analysis asks whether prices for the same commodity in geographically separated markets move together — and how quickly and symmetrically a price change in one market is transmitted to another. Martin Ravallion's 1986 article 'Testing Market Integration', using Bangladesh rice prices, se

2 sources1986
statistics

Aligned Rank Transform ANOVA

The Aligned Rank Transform ANOVA (ART-ANOVA) is a nonparametric factorial hypothesis test that detects main effects and interactions in designs with two or more independent variables, without requiring normality. The procedure was formalized by Wobbrock, Findlater, Gergle, and Higgins in their 2011 CHI paper and operat

1 source2011
economics

Almost Ideal Demand System

The Almost Ideal Demand System (AIDS), introduced by Angus Deaton and John Muellbauer in 1980, is the workhorse flexible demand system in applied microeconomics. It models each good's budget share as a linear function of the logarithms of all prices and of log real total expenditure, derived from a flexible (PIGLOG) co

1 source1980
finance

Altman Z-Score

The Altman Z-Score is a linear discriminant model developed by Edward I. Altman in 1968 to predict corporate bankruptcy using five accounting-based financial ratios. Derived through multiple discriminant analysis on a matched sample of 66 US manufacturing firms, the model combines liquidity, profitability, leverage, so

1 source1968
archaeology

Amino Acid Racemization

Amino acid racemization (AAR) dating estimates the age of biogenic materials such as mollusc shell, ostrich eggshell, bone, and teeth from the slow chemical conversion of amino acids from one mirror-image form to the other after an organism dies. Living tissue builds proteins almost entirely from left-handed (L) amino

2 sources1997
research statistics

Analysis of Variance (ANOVA)

ANOVA is a parametric statistical method developed by Ronald A. Fisher in 1925 that tests whether means differ significantly across three or more independent groups. By partitioning total variance into between-group and within-group components, ANOVA determines whether observed differences are likely due to treatment e

2 sources1925
accounting

Analytical Procedures in Auditing

Analytical procedures are evaluations of financial information made by studying plausible relationships among both financial and non-financial data. Rather than testing individual transactions, auditors develop expectations about what numbers should be and compare them to actual results, investigating significant diffe

2 sources1983
statistics

ANCOVA

ANCOVA is a parametric hypothesis test that compares the adjusted means of two or more independent groups while statistically controlling for one or more continuous covariates. By removing the portion of outcome variance explained by the covariate, ANCOVA increases statistical precision and produces fairer group compar

1 source1932
statistics

Anderson-Darling Test

The Anderson-Darling test is an empirical distribution function (EDF) goodness-of-fit test, introduced by Anderson and Darling in 1952, that checks whether a continuous sample comes from a specified distribution such as the normal, exponential, or Weibull. By weighting deviations more heavily in the tails, it detects d

2 sources1952
econometrics

Anderson-Hsiao IV

The Anderson-Hsiao IV estimator is a method for consistently estimating dynamic panel data models that include a lagged dependent variable as a regressor. Proposed by Theodore Anderson and Cheng Hsiao in 1981, it resolves the Nickell bias that arises when fixed effects are eliminated by first-differencing, by instrumen

1 source1981
economic history

Anthropometric History

Anthropometric history reads the material conditions of the past from the human body itself, using mean adult stature by birth cohort as a barometer of the biological standard of living. Final height reflects net nutritional status during the growth years—the food a child consumed minus the energy claimed by disease an

2 sources1995
econometrics

APARCH

APARCH, introduced by Ding, Granger, and Engle (1993) while studying long-memory properties of stock market returns, extends the GARCH family by allowing both the power transformation of conditional volatility and an asymmetric response to positive and negative shocks. The model nests at least seven well-known ARCH-typ

1 source1993
simulation

Approximate Bayesian Computation

Approximate Bayesian Computation (ABC) is a family of simulation-based inference methods that estimate posterior distributions without requiring an analytically tractable likelihood function. Introduced by Beaumont, Zhang and Balding (2002) in the context of population genetics, ABC replaced the intractable likelihood

2 sources2002
bayesian

Approximate Bayesian Computation with Measurement Error

Approximate Bayesian Computation with measurement error (ABC-ME) extends the standard ABC likelihood-free framework to settings where observed data are themselves noisy or imprecisely recorded. By explicitly incorporating a measurement-error kernel into the acceptance step, ABC-ME targets the correct posterior over mod

2 sources2013
bayesian

Approximate Bayesian Computation with Missing Data

Approximate Bayesian Computation with missing data extends the likelihood-free ABC framework to settings where observations are incomplete or partially recorded. By simulating data under a posited model and accepting parameter draws whose simulated summary statistics are close to the observed ones, it bypasses the need

2 sources2002
econometrics

ARCH model

The ARCH model, introduced by Robert Engle in 1982, captures time-varying volatility in financial and macroeconomic time series. It models the conditional variance of today's error as a function of past squared errors, explaining why volatile periods cluster together — a phenomenon known as volatility clustering.

2 sources1982
econometrics

ARCH-LM Test

The ARCH-LM test is Robert Engle's (1982) Lagrange multiplier diagnostic for autoregressive conditional heteroscedasticity in the residuals of a fitted time-series model. It checks whether the error variance changes over time and clusters into calm and turbulent periods, and it is the standard pre-test run before fitti

2 sources1982
econometrics

ARDL Bounds Test

The ARDL bounds test is an autoregressive distributed lag method that tests for a cointegrating (long-run level) relationship between time series, introduced by Pesaran, Shin and Smith in 2001. Unlike the Johansen procedure, it remains valid whether the variables are I(0), I(1) or a mix of the two, and it is more relia

2 sources2001
social epidemiology

Area Deprivation Index

The Area Deprivation Index (ADI) summarizes the socioeconomic disadvantage of a small geographic area, such as a census block group, into a single rankable score built from census indicators of income, education, employment, and housing. Gopal Singh constructed the modern US version in 2003, combining seventeen census

2 sources2003
human geography

Areal Interpolation

Areal interpolation is the family of methods for transferring attribute data — populations, counts, rates — from one set of areal units (the source zones) onto a different, incompatible set (the target zones). The need arises constantly in geography because census tracts, postal zones, electoral districts, and grid cel

1 source1979
econometrics

Arellano-Bond GMM estimator

The Arellano-Bond GMM estimator is the standard approach for dynamic panel data models in which the lagged dependent variable appears as a regressor. By first-differencing to remove fixed effects and using deeper lags as instruments, it yields consistent estimates even when the error is serially correlated and regresso

2 sources1991
econometrics

ARFIMA Model

ARFIMA is a time series model that captures long-memory behaviour using a fractional differencing parameter d, generalising the integer differencing of ARIMA. It was introduced by Granger and Joyeux (1980) and formalised by Hosking (1981) to describe series whose autocorrelations decay slowly rather than abruptly.

2 sources1980
archaeology

Argon-Argon Dating

Argon-argon (40Ar/39Ar) dating is the modern, high-precision successor to conventional potassium-argon dating, in which the parent potassium is measured indirectly by converting it to a measurable argon isotope inside a nuclear reactor. A potassium-bearing sample is irradiated so that potassium-39 transmutes into argon

1 source1999
econometrics

ARIMA

ARIMA is a univariate time-series forecasting model that combines autoregressive, integrated (differencing), and moving-average components to predict a single continuous series from its own past. It is the centrepiece of the Box-Jenkins methodology set out in Box, Jenkins, Reinsel & Ljung's Time Series Analysis (5th ed

1 source2015
econometrics

ARIMA model

The ARIMA(p,d,q) model is the standard workhorse for univariate time series forecasting. It combines autoregressive terms (past values), differencing to induce stationarity, and moving average terms (past shocks) into a unified linear framework. Developed by Box and Jenkins (1970), it remains one of the most widely app

2 sources1970
econometrics

ARMA model

The ARMA(p,q) model describes a stationary time series as a combination of two components: an autoregressive part that regresses the current value on its own past p values, and a moving average part that accounts for past q error terms. It is the foundational framework of the Box-Jenkins methodology for univariate time

2 sources1970
demography

Arriaga Decomposition

Arriaga decomposition is a demographic technique that breaks down the difference in life expectancy between two life tables — two countries, two time points, or two groups — into the contributions of mortality change at each age. Introduced by Eduardo Arriaga in 1984, it tells the analyst not just that life expectancy

2 sources1984
development studies

Asset Index Construction

Asset index construction builds a proxy for household wealth or socioeconomic status from observable possessions — durable goods, housing quality, and access to utilities — when reliable income or consumption data are unavailable. The dominant approach, popularized by Deon Filmer and Lant Pritchett in 2001, applies pri

2 sources2001
development studies

Asset Poverty Trap Analysis

Asset Poverty Trap Analysis tests whether households face nonlinear asset dynamics that can trap them in persistent poverty, using panel data on what households own rather than on what they earn. Developed by Michael Carter and Christopher Barrett (2006), the approach estimates the asset recursion — how a household's a

2 sources2006
sociology

Atkinson Index

The Atkinson index is a welfare-based measure of inequality that incorporates an explicit, analyst-chosen parameter for how much society dislikes inequality. Introduced by Anthony Atkinson in 1970, it asks what fraction of total income could be discarded, under an equal distribution, while leaving social welfare unchan

2 sources1970
environmental sociology

Attitude-Behavior-Context Model (ABC)

The attitude-behavior-context (ABC) framework explains environmentally significant behavior as the joint product of internal attitudes and external contextual conditions, and crucially as their interaction rather than their sum. Gregory Guagnano, Paul Stern, and Thomas Dietz proposed it in 1995 using a natural experime

2 sources1995
marketing

Attraction Market-Share Model

The attraction market-share model expresses each brand's market share as its own 'attraction' divided by the total attraction of all brands competing in the market, guaranteeing shares that are non-negative and sum to one by construction. Its theoretical foundation is the 1975 'market share theorem' of Bell, Keeney, an

2 sources1975
statistics

Attributes Control Chart

Attributes control charts extend Shewhart's framework to count and proportion data — quality characteristics that are classified rather than measured. The p- and np-charts monitor the proportion or number of defective items using the binomial distribution, while the c- and u-charts monitor the number of defects per uni

2 sources1931
econometrics

Augmented Dickey-Fuller Test

The Augmented Dickey-Fuller (ADF) test is the most widely used test for a unit root — that is, for whether a time series is non-stationary and must be differenced before modelling. Introduced by David Dickey and Wayne Fuller in 1979 and extended by Said and Dickey in 1984 to series with higher-order autocorrelation, it

2 sources1979
econometrics

Augmented Dickey-Fuller unit root test

The Augmented Dickey-Fuller test is the standard procedure for determining whether a univariate time series contains a unit root — that is, whether the series is non-stationary. It extends the original Dickey-Fuller test by including lagged difference terms that absorb serial correlation in the residuals, making the te

2 sources1979
econometrics

Augmented Mean Group Estimator

The Augmented Mean Group estimator, developed by Eberhardt and Teal (2010), is a panel data method for estimating heterogeneous slope coefficients in the presence of cross-sectional dependence. It approximates the unobserved common dynamic process driving all units and folds it into unit-by-unit regressions, then avera

2 sources2010
deep learning

Autoformer

Autoformer is a deep learning architecture for long-term time-series forecasting, introduced by Wu et al. from Tsinghua University at NeurIPS 2021. It replaces the standard self-attention mechanism with an Auto-Correlation mechanism that exploits periodic dependencies in the frequency domain, and embeds a progressive s

1 source2021
bayesian

Automatic Differentiation Variational Inference

Automatic Differentiation Variational Inference (ADVI) is a black-box algorithm for approximate Bayesian posterior inference, introduced by Kucukelbir, Tran, Ranganath, Gelman, and Blei (2017, JMLR). Given any probabilistic model whose log-joint density is differentiable, ADVI automatically transforms constrained laten

3 sources2017
electrical engineering

Automatic Test Pattern Generation

Automatic Test Pattern Generation (ATPG) is the automated creation of test vectors that detect manufacturing defects in digital circuits. Pioneered by Roth in 1966, ATPG systematically finds inputs that make stuck-at faults observable at outputs, enabling comprehensive fault detection. ATPG is critical for semiconducto

3 sources1966