It's important to know that internal and external validity don't always align. Typically, if you eliminate or control extraneous variables in your research to increase internal validity, it becomes less likely that you can replicate your research in real-world situations, which decreases external validity.
What is the meaning of 'external validity'?
External validity refers to the ability of a study’s findings to be generalized or applied to other situations outside of the experimental research setting. Researchers are interested in increasing the study’s external validity because it enables them to make well-founded claims about what they have observed.
What are potential threats to internal validity?
What are the threats to internal validity quizlet?
- History threat.
- Maturation threat.
- Testing threat.
- Instrumentation threat.
- Mortality threat.
- Regression threat.
- Selection threat.
- Social interaction threat.
What is the definition of internal validity?
The internal validity definition in science is a clear relationship between an independent and dependent variable in a study. Internal validity in research is important because causality is the strongest statement in research, meaning that true causality proves a relationship most, though it is complicated to achieve.
What is internal and external validity in psychology?
Internal validity refers to the degree of confidence that the causal relationship being tested is trustworthy and not influenced by other factors or variables.. External validity refers to the extent to which results from a study can be applied (generalized) to other situations, groups or events.
Can you have external validity without internal validity?
Lack of internal validity implies that the results of the study deviate from the truth, and, therefore, we cannot draw any conclusions; hence, if the results of a trial are not internally valid, external validity is irrelevant.
How are internal and external validity related?
Internal validity examines whether the study design, conduct, and analysis answer the research questions without bias. External validity examines whether the study findings can be generalized to other contexts.
What factors affect external validity?
There are seven threats to external validity: selection bias, history, experimenter effect, Hawthorne effect, testing effect, aptitude-treatment and situation effect.
Do experiments have internal validity external validity or both?
An experimental design is expected to have both internal and external validity. Internal validity is the most important requirement, which must be present in an experiment before any inferences about treatment effects are drawn. To establish internal validity, extraneous validity should be controlled.
Is internal validity a prerequisite to external validity replication?
External validity is the degree to which the conclusions in a study would hold for other persons in other places and at other times. As such, internal validity is a prerequisite for external validity.
How can internal and external validity be increased in an experiment?
Internal validity can be improved by controlling extraneous variables, using standardized instructions, counter balancing, and eliminating demand characteristics and investigator effects.
What are the 4 threats to external validity?
In this section, four of the main threats to external validity that you may face in your research are discussed with associated examples. These include: (a) selection biases; (b) constructs, methods and confounding; (c) the 'real world' versus the 'experimental world'; and (d) history effects and maturation.
Do confounding variables affect external validity?
External validity is one of the most difficult types of validity to achieve. One reason for this is that steps to make external validity high often result in a lowering of internal validity. Another reason is the multitudes of hidden and confounding variables that can affect your experimental outcome.
Does sample size affect internal or external validity?
The use of sample size calculation directly influences research findings. Very small samples undermine the internal and external validity of a study. Very large samples tend to transform small differences into statistically significant differences - even when they are clinically insignificant.
What is the relationship between external validity and ecological validity?
External validity examines whether the study findings can be generalized to other contexts. Ecological validity examines, specifically, whether the study findings can be generalized to real-life settings; thus ecological validity is a subtype of external validity.
How does construct validity relate to external validity?
Like external validity, construct validity is related to generalizing. But, where external validity involves generalizing from your study context to other people, places or times, construct validity involves generalizing from your program or measures to the concept of your program or measures.
What are internal and external validity and how are they important in Psychological Science quizlet?
Internal validity is the degree to which a study controls for alternative explanations; External validity is the degree to which the findings generalize to other settings; Both are important in ensuring that the researchers are answering the intended question.
What is the difference between internal validity and external validity quizlet?
Internal validity is the amount of certainty that the independent variable influenced the dependent variable. External validity is the ability to generalize the research.
What is internal validity?
Internal validity refers to the degree of confidence that the causal relationship being tested is trustworthy and not influenced by other factors or variables. External validity refers to the extent to which results from a study can be applied (generalized) to other situations, groups or events. The validity of a study is largely determined by ...
What are the two types of external validity?
The two types of external validity are population validity (whether you can generalize to other groups of people) and ecological validity (whether you can generalize to other situations and settings).
What is the degree of confidence that the causal relationship you are testing is not influenced by other factors or variables?
I nternal validity is the degree of confidence that the causal relationship you are testing is not influenced by other factors or variables.
Why is experimental design important?
Experimental design is essential to the internal and external validity of your experiment.
How is the validity of a study determined?
The validity of a study is largely determined by the experimental design. To ensure the validity of the tools or tests you use, you also have to consider measurement validity.
Is internal validity better than external validity?
Better internal validity often comes at the expense of external validity (and vice versa). The type of study you choose reflects the priorities of your research.
What is internal validity?
Internal validity is defined as the extent to which the observed results represent the truth in the population we are studying and, thus, are not due to methodological errors. In our example, if the authors can support that the study has internal validity, they can conclude that prone positioning reduces mortality among patients with severe ARDS. The internal validity of a study can be threatened by many factors, including errors in measurement or in the selection of participants in the study, and researchers should think about and avoid these errors.
What is the validity of a study?
The validity of a research study refers to how well the results among the study participants represent true findings among similar individuals outside the study. This concept of validity applies to all types of clinical studies, including those about prevalence, associations, interventions, and diagnosis.
What is external validity?
External validity is the extent to which you can generalize the findings of a study to other situations, people, settings and measures. In other words, can you apply the findings of your study to a broader context?
What are the two types of external validity?
The two types of external validity are population validity (whether you can generalize to other groups of people) and ecological validity (whether you can generalize to other situations and settings).
What is the degree of confidence that the causal relationship you are testing is not influenced by other factors or variables?
I nternal validity is the degree of confidence that the causal relationship you are testing is not influenced by other factors or variables.
Why are threats to external validity important?
Threats to external validity are important to recognize and counter in a research design for a robust study.
How to improve ecological validity in a lab setting?
To improve ecological validity in a lab setting, you could use an immersive driving simulator with a steering wheel and foot pedal instead of a computer and mouse. This increases psychological realism by more closely mirroring the experience of driving in the real world.
What is population validity?
Population validity refers to whether you can reasonably generalize the findings from your sample to a larger group of people (the population). Population validity depends on the choice of population and on the extent to which the study sample mirrors that population. Non-probability sampling methods are often used for convenience.
What would be a good sample for higher population validity?
For higher population validity, your sample would need to include people with different characteristics ( e.g. women and students from different majors, countries, and socioeconomic backgrounds).
How does external validity affect clinical practice?
External validity can also be affected if trials have protocols that differ from usual clinical practice. For example, prior to randomisation in the RCTs of endarterectomy for symptomatic carotid stenosis, patients had to be diagnosed by a neurologist and have conventional arterial angiography, neither of which are routine in many centres. The trial intervention itself may also differ from that used in current practice, such as in the formulation and bioavailability of a drug, or the type of anaesthetic used for an operation. The same can be true of the treatment in the control group in a trial, which may use a particularly low dose of the comparator drug, or fall short of best current practice in some other way. External validity can also be undermined by too stringent limitations on the use of nontrial treatments. Any prohibition of nontrial treatments should be reported in the main trial publications, along with details of relevant nontrial treatments that were used. The timing of many interventions is also critical and should be reported when relevant.
What is the external validity of an RCT?
The external validity of an RCT also depends on whether the outcomes were clinically relevant. Many trials use “surrogate” outcomes, usually biological or imaging markers that are thought to be indirect measures of the effect of treatment on clinical outcomes. However, as well as being of questionable clinical relevance, surrogate outcomes are often misleading. There are many examples of treatments that have had a major beneficial effect on a surrogate outcome, which had previously been shown to be correlated with a relevant clinical outcome in observational studies, but where the treatments have proved ineffective or harmful in subsequent large RCTs that used these same clinical outcomes [1].
Do RCTs have external validity?
Some trials have excellent external validity, but many do not, particularly some of those performed by the pharmaceutical industry. Yet researchers, funding agencies, ethics committees, medical journals, and governmental regulators all neglect proper consideration of external validity. Judgment is left to clinicians, but reporting of the determinants of external validity in trial publications, and particularly in secondary reports and clinical guidelines, is rarely adequate and much relevant information is never published. RCTs cannot be expected to produce results that are directly relevant to all patients and all settings, but to be externally valid they should at least be designed and reported in a way that allows clinicians to judge to whom they can reasonably be applied. A consensus is required on how the design and reporting of trials could be improved in order to achieve this aim. Agreement on a list of the most important issues that should be considered by clinicians and researchers would be a helpful first step.
Is there a poor reporting of adverse effects?
Reporting of adverse effects of treatment in RCTs and systematic reviews is often poor. In a review of 192 pharmaceutical trials, less then a third had adequate reporting of adverse clinical events or laboratory toxicology [19]. Treatment discontinuation rates provide some guide to tolerability, but pharmaceutical trials often use eligibility criteria and run-in periods to exclude patients who might be prone to adverse effects.
Can RCTs be externally valid?
Strict eligibility criteria can limit the external validity of RCTs, but physicians should at least be able to select similar patients for treatment in routine practice. Unfortunately, however, reporting of trial eligibility criteria is frequently inadequate. A review of trials leading to clinical alerts by the US National Institutes of Health revealed that of an average of 31 eligibility criteria, only 63% were published in the main trial report and only 19% in the clinical alert [11]. Inadequate reporting is also a major problem in secondary publications, such as systematic reviews and clinical guidelines, where the need for a succinct message does not usually allow detailed consideration of the eligibility and exclusion criteria or other determinants of external validity.
Do pragmatic trials have greater external validity than explanatory trials?
Some of the issues that determine external validity are relevant to the distinction between pragmatic trials and explanatory trials [2], but it would be wrong to assume that pragmatic trials necessarily have greater external validity than explanatory trials. For example, broad eligibility criteria, limited collection of baseline data, and inclusion of centres with a range of expertise and differing patient populations have many advantages, but they can also make it very difficult to generalise the overall average effect of treatment to a particular clinical setting.
Is external validity of RCTs of potentially dangerous treatments?
Clinicians are usually most concerned about external validity of RCTs of potentially dangerous treatments. Complications of medial interventions are a leading cause of death in developed countries. Risks can be overestimated in RCTs, particularly during the introduction of new treatments when trials are often done in patients with very severe disease, but stringent selection of patients, confinement to specialist centres, and intensive safety monitoring usually lead to lower risks than routine clinical practice. RCTs of warfarin in nonrheumatic atrial fibrillation are good examples. All trials reported benefit with warfarin, but complication rates were much lower than in routine practice, and consequent doubts about external validity are partly to blame for major underprescribing of warfarin, particularly in the elderly [1].
Why does the DV change?
Values of the DV change because of faulty equipment, the human scorer gets tired etc... That is, changes in the DV which result from changes/errors in the recording device (whether synthetic or human)
Is an experiment internally valid?
An experiment is internally valid if there are no confounds.... that is, the only reason why the groups are different (with respect to the DV) is “actually and only” because of differences in the IV
Trade-Off Between Internal and External Validity
- Better internal validity often comes at the expense of external validity (and vice versa). The type of studyyou choose reflects the priorities of your research. A solution to this trade-off is to conduct the research first in a controlled(artificial) environment to establish the existence of a causal relationship, followed by a field experiment to ...
Threats to Internal Validity
- There are eight factors that can threaten the internal validityof your research. They are explained below using the following example:
Threats to External Validity
- There are three main factors that might threaten the external validity of our study example. There are various other threats to external validitythat can apply to different kinds of experiments.