Utforsk vitenskapen etter metode, felt og evidens.

Floor and Ceiling Effect

Floor and ceiling effects are psychometric phenomena in which a disproportionately large proportion of respondents achieve the lowest (floor) or highest (ceiling) possible score on a measurement scale. These effects compromise scale reliability and responsiveness, limiting the instrument's ability to distinguish among

3 kilder2000

positive psychology

Flourishing Scale

The Flourishing Scale (FS) is an 8-item measure of human flourishing developed by Diener and colleagues in 2010. It assesses psychological well-being across core dimensions including purpose, social connection, competence, and engagement. The scale operationalizes Aristotle's concept of eudaimonia—the realization of hu

1 kilde2010

social media psychology

FoMO Scale

The FoMO Scale is a 10-item self-report instrument that measures the extent to which individuals experience anxiety or apprehension about missing out on social events, experiences, or information shared by others, particularly in social media contexts. Developed by Przybylski and colleagues in 2013, it quantifies this

1 kilde2013

Friendship Quality Questionnaire

The Friendship Quality Questionnaire is a self-report instrument designed to assess the quality and characteristics of friendships in children, adolescents, and adults. Developed by Jeffrey Parker and Steven Asher in 1993 and expanded by Bukowski and colleagues, the FQQ measures dimensions of friendship quality includi

neuropsychology

Frontal Assessment Battery

The Frontal Assessment Battery (FAB) is a brief, clinician-administered neuropsychological battery designed to assess frontal lobe function and executive abilities at the bedside. Developed by Dubois and colleagues at the Salpêtrière Hospital in Paris in 2000, the FAB consists of six subtests measuring conceptualizatio

3 kilder2000

Functional Behavioral Assessment

Functional Behavioral Assessment (FBA) is a systematic process for identifying the environmental and behavioral factors that maintain or contribute to a target behavior. Developed by Richard O'Neill, Robert Horner, and colleagues in the 1990s, FBA is a cornerstone of applied behavior analysis and is widely used in educ

2 kilder1997

Fuzzy-Set Qualitative Comparative Analysis

Fuzzy-Set Qualitative Comparative Analysis (fsQCA) is a set-theoretic method developed by Charles Ragin in the early 2000s that combines the configurational logic of qualitative case studies with the mathematical rigor of fuzzy sets. It bridges qualitative and quantitative research by allowing researchers to examine ca

3 kilder2000

G-Theory

Generalizability Theory, developed by Lee J. Cronbach and colleagues in the 1960s and formalised by Brennan (2001), is an ANOVA-based framework that extends Classical Test Theory by decomposing observed score variance into multiple, separately identified sources of measurement error — such as raters, tasks, occasions,

2 kilder1963

General Health Questionnaire

The General Health Questionnaire-12 (GHQ-12) is a brief, 12-item self-report screening instrument for psychological distress and mental health problems in the general population. Developed by David P. Goldberg, the GHQ-12 is the most widely used short form of the longer General Health Questionnaire series. It is design

2 kilder1992

General Self-Efficacy Scale

The General Self-Efficacy Scale (GSE) is a 10-item measure assessing beliefs in one's ability to handle difficult situations and to cope with challenges through adaptive effort. Developed by Ralf Schwarzer and Matthias Jerusalem in the mid-1990s, the GSE operationalizes self-efficacy as a generalized confidence in one'

3 kilder1995

Generalizability Theory

Generalizability Theory is a psychometric framework that decomposes observed score variance into multiple sources — persons, items, raters, occasions, and their interactions — using analysis of variance. It replaces the single reliability coefficient of classical test theory with a family of coefficients that tell rese

2 kilder1963

Generalized Anxiety Disorder Scale

The Generalized Anxiety Disorder-7 (GAD-7) is a brief, 7-item self-report instrument for screening and assessing the severity of anxiety symptoms in primary care and mental health settings. Developed by Spitzer and colleagues in 2006, the GAD-7 mirrors the structure and validation approach of the widely successful PHQ-

2 kilder2006

Generalized Anxiety Disorder-7

The GAD-7 is a brief 7-item self-report questionnaire designed to screen for and measure the severity of generalized anxiety disorder in adolescents and adults. Developed by Spitzer, Kroenke, Williams, and Löwe in 2006, it has become one of the most widely used anxiety screening tools in primary care, mental health res

1 kilde2006

bereavement psychology

GEQ

The Grief Experience Questionnaire (GEQ) is a multidimensional measure developed by Barrett and Schneweis in 1980 to assess the breadth of emotional, cognitive, and existential experiences reported by bereaved individuals. Rather than focusing on pathology or symptom severity, the GEQ captures the diverse phenomenology

1 kilde1980

Geriatric Depression Scale

The Geriatric Depression Scale (GDS) is a 30-item self-report depression screening instrument specifically designed for older adults. Developed by Yesavage, Brink, and colleagues in 1982, the GDS addresses the unique presentation of depression in aging populations, where symptoms may differ from younger adults. A valid

2 kilder1982

environmental psychology

GPIS

The Green Purchase Intention Scale (GPIS) measures consumers' stated willingness and likelihood of purchasing environmentally friendly products, including their intention to pay premium prices for eco-labeled goods and their perceived value of sustainable alternatives. Developed from consumer behavior and willingness-t

3 kilder1991

positive psychology

Gratitude Questionnaire

The Gratitude Questionnaire-Six (GQ-6), developed by McCullough, Emmons, and Tsang in 2002, is a 6-item measure of dispositional gratitude—the tendency to recognize and appreciate the good in one's life. Operationalizing gratitude as a stable personality trait (not just a momentary feeling), the GQ-6 assesses the capac

1 kilde2002

Grit Scale

The Grit Scale is a 12-item measure assessing grit—the combination of perseverance (sustained effort despite obstacles) and passion (consistent interest and commitment) for long-term goals. Developed by Angela Duckworth and colleagues in 2007, the GRIT operationalizes grit as a distinct personality construct predicting

3 kilder2007

sport psychology

Group Environment Questionnaire

The GEQ is an 18-item instrument measuring team cohesion—the degree to which team members feel attracted to the group and perceive the group as unified around shared task and social goals. Developed by Carron, Widmeyer, and Brawley in 1985, the GEQ has become the gold standard for measuring cohesion in sport teams and

2 kilder1985

Guttman Scale

Guttman scaling is a methodology for constructing unidimensional scales with a cumulative property, developed by Louis Guttman in 1944. The method assumes that items form a perfect or near-perfect hierarchy: if a respondent endorses a harder item, they must endorse all easier items below it. This creates a reproducible

3 kilder1944

Hamilton Anxiety Rating Scale

The Hamilton Anxiety Rating Scale (HAM-A) is a clinician-administered assessment tool for quantifying the severity of anxiety symptoms in adults. Developed by Max Hamilton in 1959, it remains one of the most widely used instruments for evaluating anxiety in clinical and research settings. The scale measures both psycho

2 kilder1959

Hamilton Depression Rating Scale

The Hamilton Depression Rating Scale, published by Max Hamilton in 1960, is a clinician-administered interview assessment of depressive symptom severity. The most common version contains 17 items (HAM-D-17), though 21-item and 24-item versions exist. It is considered the gold standard outcome measure in antidepressant

3 kilder1960

forensic psychology

HCR-20v3

The HCR-20v3 is a structured professional judgment framework developed by Douglas, Hart, and colleagues for the assessment of risk for violence among adolescents and adults in mental health, criminal justice, and forensic settings. Published in 2013, it represents the third version of one of the most widely validated r

2 kilder2013

psychotherapy research

Helpful Aspects of Therapy Form

The Helpful Aspects of Therapy (HAT) form is a semi-structured client feedback instrument designed to capture the client's perception of what was most beneficial or helpful in a therapy session or course of treatment. Developed by Llewellyn and refined by Elliott, the HAT combines open-ended narrative response with str

2 kilder1988

bereavement psychology

HGRC

The Hogan Grief Reaction Checklist (HGRC) is a 61-item comprehensive measure developed by Nancy S. Hogan and colleagues in 2001 to assess the full spectrum of grief reactions—encompassing not only grief distress and symptoms but also post-loss growth and resilience. Unique among grief instruments, the HGRC explicitly m

1 kilde2001

Hospital Anxiety and Depression Scale

The Hospital Anxiety and Depression Scale (HADS) is a 14-item self-report instrument measuring anxiety and depression symptoms in medically ill populations. Developed by Zigmond and Snaith in 1983, the HADS was specifically designed for hospital and general medical settings where somatic symptoms of medical illness may

2 kilder1983

psychology of religion

I/E Religiosity Scale

The I/E Scale, originally developed by Allport and Ross in 1967, is a foundational measure in the psychology of religion that distinguishes between two motivational orientations toward religion: intrinsic (religion as end in itself, source of meaning) versus extrinsic (religion as means to social, personal, or practica

2 kilder1967

IAT

The IAT is a 20-item self-report questionnaire designed to measure problematic internet use and internet addiction. Developed by Kimberly Young in 1998, it was one of the first validated screening tools for internet-related compulsive use. The IAT assesses loss of control, salience (preoccupation with internet), withdr

3 kilder1998

trauma psychology

Impact of Event Scale Revised

The IES-R is a 22-item self-report scale measuring subjective distress from a specific traumatic event. Developed by Weiss and Marmar in 1997 as a revision of the original 1979 Impact of Event Scale, it assesses posttraumatic stress symptoms along three core dimensions: intrusion, avoidance, and hyperarousal. The scale

2 kilder1997

psychology

Implicit Association Test

The Implicit Association Test (IAT) is a computerized measure designed to detect automatic associations between concepts in memory, such as implicit attitudes toward social groups or implicit self-concepts. Introduced by Greenwald, McGhee, and Schwartz in 1998, it infers the strength and valence of associations from th

3 kilder1998

psychiatry

Insomnia Severity Index

The ISI is a 7-item self-report questionnaire designed to assess the severity of insomnia in adolescents and adults. Developed by Morin and colleagues and validated in 2001, it measures difficulty falling asleep, difficulty staying asleep, early morning awakening, and daytime functional impairment due to sleep problems

3 kilder2001

Interpersonal Reactivity Index

The Interpersonal Reactivity Index (IRI) is a 28-item self-report measure developed by Mark H. Davis in 1980 to assess individual differences in empathy as a multidimensional construct. Rather than treating empathy as a single trait, the IRI measures four distinct empathic dimensions: perspective-taking, fantasy, empat

2 kilder1980

Interpersonal Therapy Assessment

Interpersonal Therapy (IPT) assessment is a structured evaluation of the client's current symptoms and their interpersonal context to identify one or more core interpersonal problems (grief, disputes, role transitions, or interpersonal deficits) maintaining the client's psychological distress. Developed by Gerald Klerm

2 kilder1984

Intolerance of Uncertainty Scale

The IUS-12 is a 12-item self-report measure of intolerance of uncertainty, a cognitive vulnerability factor underlying anxiety across multiple disorders. Developed by Carleton, Norton, and Asmundson in 2007 as short form of the original IUS-27, it measures difficulty accepting or managing uncertainty and associated anx

1 kilde2007

psychology

Iowa Gambling Task

The Iowa Gambling Task (IGT) is a laboratory analog of real-world decision-making that measures how individuals make risky choices when outcomes are uncertain. Participants select cards from four decks, each offering different patterns of rewards and losses. The task reveals whether participants learn from experience t

3 kilder1994

social media psychology

Iowa-Netherlands Social Comparison Orientation Scale

The Iowa-Netherlands Comparison Orientation Measure (INCOM) is an 11-item self-report scale that assesses individual differences in the tendency to engage in social comparison—comparing oneself to others on abilities, attributes, and outcomes. Developed by Gibbons and Buunk in 1999, it captures both upward comparison (

1 kilde1999

Item Analysis

Item analysis is the foundational psychometric procedure for evaluating the quality of individual test or scale items within the Classical Test Theory (CTT) framework, as systematised by Allen and Yen (1979) and Crocker and Algina (1986). It produces an item difficulty index, an item discrimination index, and a distrac

2 kilder1979

Item Response Theory

Item response theory models the probability that a respondent answers an item correctly (or endorses it) as a function of the respondent's latent trait level and the item's own statistical properties — difficulty, discrimination, and guessing. Unlike classical test theory, IRT places persons and items on the same scale

2 kilder1952

Kessler Psychological Distress Scale

The Kessler Psychological Distress Scale-10 (K10) is a 10-item self-report measure of non-specific psychological distress and mental health problems. Developed by Kessler and colleagues in 2002, the K10 was designed as an ultra-brief screening instrument for population surveys and epidemiological research. A shorter 6-

2 kilder2002

psychology

Lexical Decision Task

The Lexical Decision Task is a computerized measure of word recognition and semantic processing. Participants judge whether letter strings are real words or nonwords (pronounceable but meaningless letter combinations). Response times and accuracy reveal how quickly people access word meanings, how semantic relatedness

3 kilder1971

Liebowitz Social Anxiety Scale

The Liebowitz Social Anxiety Scale (LSAS) is a 24-item clinician-administered scale designed to measure the severity of social anxiety and avoidance in individuals with social anxiety disorder. Developed by Michael R. Liebowitz in 1987, the LSAS has become the gold-standard instrument for assessing social phobia in cli

1 kilde1987

trauma psychology

Life Events Checklist for DSM-5

The LEC-5 is a 17-item self-report checklist assessing exposure to stressful life events that may result in PTSD or trauma-related mental health problems. Developed by Weathers and colleagues at the National Center for PTSD in 2013, the LEC-5 identifies which types of traumatic events a person has experienced, determin

2 kilder2013

positive psychology

Life Orientation Test Revised

The Life Orientation Test – Revised (LOT-R) is a 10-item measure of dispositional optimism developed by Scheier, Carver, and Bridges in 1994. It assesses the general expectancy that good things (versus bad things) will happen in the future. Optimism, as measured by the LOT-R, predicts coping success, health outcomes, a

1 kilde1994

Likert Scale Construction

Likert scale construction is a systematic methodology for developing attitude measurement instruments using summated rating scales. Introduced by Rensis Likert in 1932, it enables researchers to quantify latent constructs such as attitudes, beliefs, and psychological states by aggregating responses across multiple item

3 kilder1932

Longitudinal Construct Validity

Longitudinal construct validity evaluates whether a psychological scale measures the same latent construct in the same way across multiple time points. It is tested by progressively constraining a confirmatory factor model across waves and comparing model fit, ensuring that observed change scores reflect genuine change

Longitudinal content validity

Longitudinal content validity evaluates whether the items of a measure adequately and consistently represent the intended content domain not only at a single point in time but across repeated administrations. It ensures that the conceptual coverage of a scale remains appropriate and stable as measurement occasions accu

2 kilder1995

Longitudinal convergent validity

Longitudinal convergent validity evaluates whether a scale's indicators correlate with theoretically related constructs not just at a single time point but consistently across repeated measurement occasions. It extends standard convergent validity testing into longitudinal designs to ensure that the scale measures the

2 kilder1997

Longitudinal DIF

Longitudinal differential item functioning detects whether individual test or scale items behave differently across measurement occasions for the same respondents. It extends standard DIF methodology to repeated-measures designs, ensuring that observed change scores genuinely reflect construct change rather than shifts

2 kilder1980

Longitudinal Discriminant Validity

Longitudinal discriminant validity tests whether a psychological construct measured at two or more time points is empirically distinct across occasions — ensuring that the same construct does not collapse into a single undifferentiated mass over time. It is a prerequisite for meaningful change modeling in panel and lon

Longitudinal Generalizability Theory

Longitudinal generalizability theory extends classical G-theory to repeated-measures and longitudinal designs, decomposing score variance across persons, measurement occasions, raters, and items simultaneously. It quantifies how reliably scores can be generalized across time points, evaluators, and conditions — informa

2 kilder1990

Longitudinal IRT

Longitudinal IRT extends classical item response theory to data collected at multiple time points, allowing researchers to model both the initial latent trait level and its change over time. It is used in educational assessment, clinical trials, and panel studies where the same items or item banks are administered repe

2 kilder1991

Longitudinal McDonald's omega

Longitudinal McDonald's omega estimates scale reliability separately at each measurement occasion in a panel or repeated-measures study. By fitting a confirmatory factor model at each wave, it tracks how consistently a set of items measures its target construct over time, detecting erosion or improvement in measurement

2 kilder1999

Longitudinal Measurement Invariance

Longitudinal measurement invariance testing determines whether a psychological scale measures the same construct in the same way across two or more time points. It is a prerequisite for interpreting mean-level change scores in panel and repeated-measures studies, ensuring that observed change reflects true change in th

Longitudinal Nomological Validity

Longitudinal nomological validity evaluates whether a construct's theoretically predicted relationships with other constructs hold consistently across multiple measurement occasions. It extends the nomological network framework of Cronbach and Meehl (1955) to longitudinal designs, testing whether a scale behaves as the

2 kilder1955

Longitudinal Reliability Analysis

Longitudinal reliability analysis evaluates the consistency and stability of measurement instruments across two or more time points. It extends classical reliability concepts — internal consistency, test-retest stability, and measurement precision — to repeated-measures designs, ensuring that observed score changes ref

2 kilder1951

Longitudinal scale development

Longitudinal scale development is the systematic process of constructing and validating a measurement instrument using data collected at multiple time points. It extends classical scale development by additionally testing whether the scale measures the same construct in the same metric across occasions, enabling valid

2 kilder1990