Statistical Analysis Stack Exchange
Statistical Analysis Stack Exchange

Questions tagged [validity]

An instrument is valid if it measures what it purports to measure. This is different from reliability, which means that an instrument measures (whatever it measures) in a way that is repeatable. DO NOT use this tag for `validation` model purposes.

References: Wikipedia and CV Meta's thread

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How to NOT use statistics

This is sort of an open ended question but I wanna be clear. Given a sufficient population you might be able to learn something (this is the open part) but whatever you learn about your population, when is it ever applicable to a member of the…
John Leidegren
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Identification of useless questions from a questionnaire

I'm developing a questionnaire. To improve its reliability and validity I want to use statistical methods. I want to eliminate questions whose answers are always the same. This means that nearly all participants gave the same answers on those…
Max
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How to reduce number of items using factor analysis, internal consistency, and item response theory in conjunction?

I am in the process of empirically developing a questionnaire and I will be using arbitrary numbers in this example to illustrate. For context, I am developing a psychological questionnaire aimed at assessing thought patterns commonly identified in…
Behacad
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Does a statistic used as a measure becomes invalid after it's reported on?

Apologies if this the wrong place to ask. but i'm trying to explain to a director that his Statistics don't show the truth because he is demanding that the stats are what is reported on and staff are measured against. But my explanations don't get…
Blade Wraith
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Looking for a good online resource about survey design and analysis

What is a good and relatively brief overview of good practice for getting valid results from surveys. I'm particularly interested in something about good survey design and analysis.
Christian M.
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Validity of using a combination of Wilcoxon tests and Spearman rho as an alternative to GLM?

I recently read a paper where the authors used either (a) a generalised linear model or (b) a combination of Wilcoxon rank sum tests and Spearman’s rank correlation, depending on whether the data followed a normal distribution or not. They also used…
Tilen
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How high is too high with Cronbach's alpha?

Someone in my organization just sent me a scale they developed (modified items from five separate scales used in published research) to measure an employee's readiness for change. They tested the internal consistency of the 15 item scale with…
user3594490
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How can reliability and validity of content analysis be quantified when there is only one person coding the data?

How can reliability and validity of content analysis be quantified when there is only one person coding the data?
user22478
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How are Cronbach's Alpha and Average Variance Extracted different in their interpretation?

Background: I do survey research on Information Systems. I have a latent construct that I measure with six survey items and reflective measurement model. Each survey item has a seven point Likert scale. This construct and these items are embedded in…
jhg
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Can I delete excessive number of multivariate outliers, like over 10% in sample?

I have a dataset with around 9000 cases, I'm running a factor analysis and I have found that 1100 cases are identified as being a multivariate outlier. Is it alright for me to got ahead and delete it?
Emily Jones
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Validity of combining surveys and sociodemographics to estimate miles walked in census tracts

I ran across this paper that describes an interesting approach to combining survey and sociodemographic data: Salon. Estimating Total Miles Walked and Biked by Census Tract in California. State of California Department of Transportation. As stated,…
aaaabdoujaparov
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If a measure is valid (but not necesarily reliable), can it be consistently replicated?

I had this question on an exam, and I was positive that the answer was A. The Beck Depression Inventory is a scale intended to measure depression levels, with higher scores indicative of higher levels of depression. If this were a valid measure…
user125334
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How can statistics be used to avoid "Lending False Credibility To Decisions We've Already Made"

In light of this article Data Science Has Become About Lending False Credibility To Decisions We've Already Made published in Forbes, I would appreciate input from the statistical and data science community: 1. What can be done to ensure credibility…
Krantz
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What tradeoffs are there between internal and external validity?

I was reading through an article about research design. The authors gave an example on the relation between internal and external validity which I thought might be an important area of consideration when designing research proposals. "A restricted…
Derrick Mah
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What's an intuitive way to explain the different types of validity?

Specifically I'm thinking of a simplified division whereby validity is divided into: Construct validity 1a. Convergent validity 1b. Discriminant validity Criterion related validity 2a. Predictive validity 2b. Concurrent validity This division…
user1205901 - Reinstate Monica
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