Questions tagged [cronbachs-alpha]
Cronbach's $\alpha$ is an estimate of the reliability (specifically, of one its aspect called internal consistency or item-item homogeneity) of a unidimensional test, a construct. It is used mostly in psychometrics and occasionally in other disciplines.
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Measuring the reliability of a survey data
I have a survey data and I applied KR20 on it. The KR20 score is 0.63 which means this survey result is not consistent and reliable, at least not in a reliable range with the definition of a reliable ...
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Visualize Cronbach's alpha in R Ggplot scatterplot as a regression line? [closed]
I'm looking for a way to make a scatterplot of the correlation between two questionnaires using Cronbach's alpha:
Data:
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Negative Cronbach's alpha – recode data, or use another method?
Below is a made up scenario to exemplify my issue.
I have two questionnaires asking individuals how much headache they have compared with 7 days ago. The scale is from much less through little less, ...
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Is there a proof of the equivalence between Cronbach's alpha and reliability calculation from a CFA?
Given a uni-dimensional CFA, reliability can be calculated as:
$$
\omega = {\left(\sum_{i=1}^p \lambda_i\right)^2\over \left(\sum_{i=1}^p \lambda_i\right)^2 + \sum_{i=1}^p\sigma^2_i}
$$
where $\...
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How to calculate Cronbach's Alpha for a total scale that consists of four subscales?
I have a scale that has 4 subscales. Each subscale has 5 items. For calculating Cronbach's alpha for the total scale, should I use subscale values (in this case it would be 4) or should I use ...
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alpha function in R package "psych" doesn't exist anymore? [closed]
Ive always used the alpha function from the psych package to get Cronbachs alpha. I've written my script three days ago, it worked perfectly. Now it doesn't and it seems like the alpha function doesn'...
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Factor Analysis using IBM SPSS for Likert Scale
I'm running a factor analysis of a Likert questionnaire that have a Cronbach's Alpha of 0,9.
I'm trying to figure out if my process for factor analysis of the strength of the correlation between two ...
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`psych::alpha`- explained the calculation details
I noticed that someone included the total score of each item when calculating the Cronbach's alpha of the questionnaire. I don't know the reason for this?
Original link https://stackoverflow.com/...
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Can I derive the (constant) between-subscale correlation by the number of items and Cronbach's alpha both for each subscale and the global scale?
To give you an example: let's suppose I have 3 subscales A, B and C, each with 5 item, and I know
The Cronbach's alpha of each subscale (let's suppose: 0.80 for A, 0.85 for B and 0.90 for C),
The ...
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Can I delete a dimension of a scale if this dimension reach a very low internal consistency when doing psychological network analysis
I am trying to do a psychological network analysis, and I aim to do the analysis on dimension-level (summing all the items belonging to this dimension). However, I've found that one dimension of the ...
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Comparing scale worded slightly differently across 3 datasets
I am working with 3 cohorts, 2 of which received a 5-item measure (say measure A) and one that received a modified version of the same measure (measure B). Essentially, measure B is comprised of same ...
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how to deal with the accumulation of the alpha error?
I have six qualitative ( ordinal) dependent variables (psychological distress), all of which have 4 categories (from 1 to 4). and 14 independent demographic variables (e.g gender, level of education, ...
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Do I need do calculate Cronbach's alpha for previuosly validated questionnaire?
I have a study in which a well-known previously validated questionnaire (like Beck Depression Index, NEO-FFI, etc.) is used. My question is: do I need to calculate Cronbach's alpha for this ...
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What is cor.smooth(R) : Matrix was not positive definite warning Cronbach alpha in Psych?
I'm getting the warning In cor.smooth(R) : Matrix was not positive definite, smoothing was done, but what is it in this case? Can I get away with that?
code:
<...
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Is there an accepted equivalent of Cronbach's alpha when there are more items than cases
I have a test with 160 items (with binary responses), and have 135 cases (and no way of collecting more, this a dataset where collection has already ended).
Reviewers have asked for a reliability ...
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Do you have to assess reliability for non-composite scores?
I feel like this is probably a really stupid question but I'm having issues finding the answer. When I think of reliability, normally I think of several items on a test that are compiled into some ...
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Improving Cronbach Alpha after removing highly correlated questions [closed]
I am currently conducing a cronbach alpha analysis on some questionnaire data and the cronbach scores are low. I have created a correlation matrix to see which items are highly correlated and which ...
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Are Cronbach's alpha of the subscale the same as in correlated-factor model and bifactor model?
I have an instrument that holds a correlated-factor model and a bifactor model (one general model and four orthogonal factors). I need to report the reliability of each subscale. I've computed Omega (...
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What I supposed to do if Cronbach's alpha is negative? [closed]
I have 100 sample with 8 questions with answers between Yes or No (Guttman scale). Cronbach's alpha is badly negative. I have checked everything I could think of, but the result did not change. I have ...
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High Cronbach's alpha
I am doing a pilot study of 30 samples. I am getting Cronbach Alpha of 0.933 to 0.991. I tried deleting few items and running the analysis. But still Cronbach Alpha has changed much. My specific ...
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Justify the deletion of a factor in EFA
I have done an EFA on 180 observations.
In order to explain my latent variables I have considered 24 variables and I get 7 factors.
Unfortunately 2 factors among the 7 have a cronbach's alpha around 0....
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Cronbach Alpha help
I had a test that I use to evaluate participants in a quality monitoring - I want to check the reliability of the tool. I got the average of each category, can I use Cronbach alpha to check ...
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What is the ideal measure of reliability when each subject only responds to a subset of items?
Lets say I have a measure with 40 items, but each subject only responded to 20 of them. Is there a way to still calculate reliability in R?
I've looked into Robust Cronbach's Alpha using the "...
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How to identify careless responders when items negatively correlate with the total scale
I'm calculating the Cronbach's alpha on a dataset with the scores of the Coping Orientations to the Problems Experienced (COPE-NVI-25) with R and the psych package.
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Calculating inter-rater reliability with 1 primary rater and a couple other secondary raters
I'm trying to figure out what to use to calculate inter-rater reliability for a set of behavioral coding. There's one individual codes the whole set (primary coder; e.g. codes data ID 1-300) and a few ...
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Metafor Package: How to conduct Meta Regression with reliability generalization
How to conduct meta regression in "metafor" after I got I2 heterogenity 94%. My study reliability generalization alpha Cronbach, with continuous and categorical moderator variable.
Thanks ...
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Denotion of Cronbach's Alpha based on Polychorric Correlations
we assessed several 5 point Likert-Scale items in a questionnaire and are interested
in Cronbach's $\alpha$ for the internal consistency.
I recently read (here) that it can be more precise to used ...
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Correlation between subscales
I have used a scale, which includes 3 subscales. Given that the 3 subscales make part of the same,validated instrument, what conclusions can be drawn from the fact that a pair of subscales ...
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Inter-rater reliability using two raters on the same subjects
I'm very new to R, so I'm sorry if this is a really basic question.
I'm trying to calculate interrater reliability using Cronbach's alpha for two raters using the same assessment on the same six ...
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Is there any way to visualize Cronbach's alpha value and test-retest reliability (intraclass correlation coefficient) analysis outcomes?
Is there any way to visualize Cronbach's alpha value and test-retest reliability (intraclass correlation coefficient) analysis outcome?
I use Rstudio as my daily driver, so if there's any way to ...
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The correction for attenuation
The reliability of the task that I measured is very low for some sub-tasks. So, I tried to correct the correlation coefficient with Spearman's disattenuation formula: $r_{x'y'} = r_{xy}/\sqrt(r_{xx}r_{...
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Cronbachs alpha for items with different scales
I have a sample size of N=63 and 6 items measuring risk tolerance. Now, I want to calculate Cronbachs alpha, however, the 6 items have different scales. For example, the first item has a scale from 1-...
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When running a reliability analysis (using Cronbach's alpha) in SPSS, what does "scale" refer to? Do I have to compute a scale explicitly beforehand?
Is the scale meant to represent the sum of responses (each response is an element of, say, the set {1, 2, 3, 4, 5}) of a case (an individual) to a set of questions (items)? And is a "scale mean&...
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IRT: What is enough information? And can a test provide too much?
I was wondering what makes for a good test information value in IRT, and came across this:
Reliability: Item and test information functions graphically reflect
how reliably the individual items and ...
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How to use Cronbach's Alpha?
Is it appropriate to use Cronbach's Alpha for nominal variables? I have 20 nominal variables (two dimensions with 10 questions each) that ask about the characteristics of work performance.
The ...
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Fleiss' Kappa v. Cohen's Kappa v. Cronbach's Alpha
I am working on a project that compares two methods of assessing whether certain topics come up in a therapy session. I am comparing a checklist full of dichotomous (y/n) items completed by an ...
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Alternative to Cronbach's alpha if $n$ is too small for McDonald's omega?
I have a very high Cronbach's Alpha of $0.966$ (and composite reliability of $0.969$). My questionnaire has a 1-factor-structure, which makes it compatible with Cronbach's Alpha, but it has 22 items. ...
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Cronbach's alpha and reverse-scored items
When calculating Cronbach's $\alpha$, would I include the reverse scores? I have 20 items in total, including 11 reverse-scored items. Would I just calculate the original scores?
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Cronbach's Alpha with repeated missing values
I would like to use Cronbach's Alpha to check the fiability or internal consistency of a cognitive task. The task has a certain number of trials which were coded with zeros (incorrect trial) and ones (...
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Adjust alpha when switching from one-tailed t-test to two-tailed
I started with a hypothesis that says e.g. A is larger than B which would usually call for a one-tailed t-test. But after acquiring the data it turns out that the effect seems to be contrary to my ...
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Should reliability test (cronbach alpha) include missing values?
I am currently doing a reliability test for my questionnaires with 34 respondents. However, there are some missing values in the questionnaires which I'm not sure whether I need to include or exclude ...
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Is it always needed to do a validity test for variables?
Let's say I have one variable called "perceived image", which is measured with 6 items (questions) that I adapted from previous literature. If I have a Cronbach's alpha > 0.7 (for reliability), do I ...
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Unidimensionality in IRT
I recently came across the definition of unidimensionality (in the context of IRT and internal consistency reliability, specifically Cronbach's alpha). Johnsosn (2007) states that
There is a one-...
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item-total correlation vs. inter-item correlation
I am assesing the reliability and validity of an 16-item multuiple choice test supposed to test language skills. Cronbach's apha is "questionable" with .65. I am having troubles interpreting the ...
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Low internal consistency
I am currently analysing the data for a survey I have completed. In doing so, one question is quite simple (nominal) and require a typical “I do/I do not” and “I do not/I do” response from the ...
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Is it correct to a total Cronbach´s alpha analysis to a tridimensional scale?
There´s a statement that says that Cronbach´s alpha assumes unidimensionality. In that sense, is it correct to calculate a global alpha? I mean, by including all 3 dimensions, and not by separating ...
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What is the difference between Cronbach's alpha and standardized Cronbach's alpha?
I found in the wiki article a definition of a standardized Cronbach's alpha but nothing is said what it is and about its relation to the original Cronbach's alpha:
I found at What is Cronbach's ...
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How do you calculate a new scale from two given variables and then find out the cronbach-alpha?
The question concerns two variables with scores from a personality test, Ptest1 and Ptest2 with values from 60 participants from each variable. So how I can convert these two variables into a new ...
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Cronbach alpha with knowledge items?
I have a very specific question about the application of Cronbach's alpha to data with trichotomous responses (true-false-don't know). I have an acquaintance I'm helping replicate a study using a 45 ...
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Cronbach alpha and item selection
I am a relative novice when it comes to statistical analysis, so forgive me if my question is unclear, or simply stupid. I am also not a matemathician, as I work in social science research, but I have ...
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