External validity

externalExternal validity (scientific studies)generalisedgeneralizabilitygeneralizablegeneralizedvalidatesvalidationvalidity
External validity is the validity of applying the conclusions of a scientific study outside the context of that study.wikipedia
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Internal validity

validityinternalhistory
In contrast, internal validity is the validity of conclusions drawn within the context of a particular study.
It contrasts with external validity, the extent to which results can justify conclusions about other contexts (that is, the extent to which results can be generalized).

Selection bias

selection effectselectionbias
An important variant of the external validity problem deals with selection bias, also known as sampling bias—that is, bias created when studies are conducted on non-representative samples of the intended population.
A distinction of sampling bias (albeit not a universally accepted one) is that it undermines the external validity of a test (the ability of its results to be generalized to the rest of the population), while selection bias mainly addresses internal validity for differences or similarities found in the sample at hand.

Sampling bias

ascertainment biasbiased samplebias
An important variant of the external validity problem deals with selection bias, also known as sampling bias—that is, bias created when studies are conducted on non-representative samples of the intended population.
A distinction, albeit not universally accepted, of sampling bias is that it undermines the external validity of a test (the ability of its results to be generalized to the entire population), while selection bias mainly addresses internal validity for differences or similarities found in the sample at hand.

Ecological validity

ecologically valid
They criticize the lack of ecological validity in many laboratory-based studies with a focus on artificially controlled and constricted environments.
Unlike internal and external validity, ecological validity is not necessary to the overall validity of a study.

Field experiment

field experimentsfield trialsfield
Some researchers believe that a good way to increase external validity is by conducting field experiments.
Field experiments offer researchers a way to test theories and answer questions with higher external validity because they simulate real-world occurrences.

Dependent and independent variables

dependent variableindependent variableexplanatory variable
In most cases, generalizability is limited when the effect of one factor (i.e. the independent variable) depends on other factors.

Interaction (statistics)

interactioninteractionsinteraction effect
Therefore, all threats to external validity can be described as statistical interactions.

Qualitative research

qualitativequalitative methodsqualitative data analysis
Within the qualitative research paradigm, external validity is replaced by the concept of transferability.

Psychological fiction

psychological novelpsychologicalpsychological drama
It is more important to ensure that a study is high in psychological realism—how similar the psychological processes triggered in an experiment are to psychological processes that occur in everyday life.

Cover-up

cover upcoverupcover story
To accomplish this, researchers sometimes tell the participants a cover story—a false description of the study's purpose.

Reproducibility

reproduciblereplicabilityreproduce
The ultimate test of an experiment's external validity is replication — conducting the study over again, generally with different subject populations or in different settings.

Meta-analysis

meta-analysesmeta analysismeta-analytic
To make sense out of this, there is a statistical technique called meta-analysis that averages the results of two or more studies to see if the effect of an independent variable is reliable.

Reactivity (psychology)

reactivityobserver effectreactive
It is a significant threat to a research study's external validity and is typically controlled for using blind experiment designs.

Cross-cultural psychology

cross-culturalcross-cultural mediationcross-culturally
Since there are questions as to whether theories dealing with central themes, such as affect, cognition, conceptions of the self, and issues such as psychopathology, anxiety, and depression, may lack external validity when "exported" to other cultural contexts, cross-cultural psychology re-examines them using methodologies designed to factor in cultural differences so as to account for cultural variance.

STAR*D

a 2004 study
A key feature of the study was its aim to be more generalizable to real clinical situations; this was done through the use of minimal exclusion criteria, incorporating patient preference, and not blinding the treatments (i.e. the patient and clinician both knew what treatment the patient was receiving).

LGBT parenting

same-sex parentinggay parentingsame-sex parents
The review concluded that all of the studies lacked external validity and that therefore: "The conclusion that there are no significant differences in children reared by lesbian mothers versus heterosexual mothers is not supported by the published research data base."

Genome-wide complex trait analysis

GCTAgenomic analysisgenomic relatedness
Estimation in biology/animal breeding using standard ANOVA/REML methods of variance components such as heritability, shared-environment, maternal effects etc. typically requires individuals of known relatedness such as parent/child; this is often unavailable or the pedigree data unreliable, leading to inability to apply the methods or requiring strict laboratory control of all breeding (which threatens the external validity of all estimates), and several authors have noted that relatedness could be measured directly from genetic markers (and if individuals were reasonably related, economically few markers would have to be obtained for statistical power), leading Kermit Ritland to propose in 1996 that directly measured pairwise relatedness could be compared to pairwise phenotype measurements (Ritland 1996, "A Marker-based Method for Inferences About Quantitative Inheritance in Natural Populations" ).

Index of criminology articles

List of criminology topics
ecological theory – elder abuse – embezzlement – enforcement discretion – environmental crime – environmental criminology – espionage – ethnic succession – evidence collection – exile – expert witness – external validity – extortion –

Swinging (sexual practice)

swingingswingersswinger
This study, which only polled self-identified swingers, is of limited use to a broader application to the rest of society (external validity) owing to self-selected sampling.