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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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What is known about the (in)efficiency of true score variance estimation?

In classical test theory, an observed score $X$ is defined as $$ X = T + E $$ where $T$ represents the individual true score and $E$ represents the individual error score. In this context $T$ may be ...
LJ Beinhauer's user avatar
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Mean score of the Composite Variable

I have three items(Likert scale from 5 to 1) measuring opportunity recognition. I was getting negative cronbachs alpha value. Hence, I reverse-coded and got the Cronbach's alpha of 0.83. I will be ...
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How to calculate reliability of difference scores?

I am trying to calculate the reliability of a difference score. Specifically, the data have, for each participant, scores for 10 items in Condition X (1s and 0s), as well as 10 different items in ...
Altair555's user avatar
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Cronbach's alpha for knowledge pretest-posttest / control and treatment groups

I am having trouble finding clear answers to these specific questions about calculating Cronbach's alpha. For my dissertation study, I conducted a teaching intervention. I administered a pretest and ...
user405908's user avatar
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3 answers
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Cronbach alpha - descriptive statistics

I researched thinking styles based on Sternberg's Investment Theory. I used a TSI questionnaire that measures preferences in thinking styles. The problem is that I got low scores of Cronbach's alpha ...
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Cronbach alpha for non-Likert & Likert survey

I have a thesis ongoing and I have a survey that needs for reliability testing. I was advised to do a Cronbach's alpha test. My survey consists of two parts: Part 1: All questions have varying number ...
Kenzo's user avatar
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How do we decide the sample size we need for ensuring reliability for a test?

There is a test consisting of 6 questions and additional sub-Qs. The test was translated into another language and the questions were adapted, but the reliability of the test was never assessed. The ...
jordanLeah's user avatar
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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 ...
Moh-Spark's user avatar
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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: ...
Wandering_geek's user avatar
2 votes
2 answers
270 views

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, ...
Wandering_geek's user avatar
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1 answer
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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 $\...
Jayden Nord's user avatar
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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 ...
karen's user avatar
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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 ...
Saints-Sallée's user avatar
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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/...
user388013's user avatar
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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 ...
Łukasz Deryło's user avatar
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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: <...
Larissa Cury's user avatar
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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 ...
Shawn Hemelstrand's user avatar
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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 ...
Anna Caunt's user avatar
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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 (...
alex_bbxymsk's user avatar
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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 ...
Putri's user avatar
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High Cronbach's alpha

I am conducting a pilot study with a sample size of $n=30$. I am getting a Cronbach's alpha score of $0.933$ to $0.991$. I tried deleting a few items and re-running the analysis. But still, Cronbach's ...
Natraj Thimmaiah's user avatar
1 vote
2 answers
2k views

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 ...
SCR- D's user avatar
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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 "...
Dave's user avatar
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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 the R package psych. I ...
Gianluca78's user avatar
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1 answer
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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 ...
user319810's user avatar
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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 ...
Wahyu Syahputra's user avatar
1 vote
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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 ...
SysRIP's user avatar
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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 ...
LeliaBS's user avatar
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5 votes
2 answers
641 views

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 ...
Shakil Ahmed Shaon's user avatar
2 votes
1 answer
755 views

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_{...
Bahareh Jozranjbar's user avatar
1 vote
1 answer
499 views

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-...
Jensxy's user avatar
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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&...
Nada Al-Iskandaraniyyah's user avatar
2 votes
1 answer
473 views

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 ...
kh_one's user avatar
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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 ...
dr_stats's user avatar
1 vote
1 answer
2k views

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 ...
CJohnson's user avatar
2 votes
1 answer
337 views

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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1 vote
1 answer
3k views

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?
Crystal L's user avatar
1 vote
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353 views

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 (...
fedegiova's user avatar
2 votes
2 answers
601 views

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 ...
Nilo's user avatar
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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 ...
lindsey 96's user avatar
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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 ...
Tom's user avatar
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2 votes
1 answer
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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-...
user1607's user avatar
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1 vote
1 answer
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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 ...
user1607's user avatar
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1 vote
2 answers
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Cronbach's Alpha of Likert Item

My questionnaire consists of ten 5-point scaled Likert items. If the Likert items have a good Cronbach alpha, is it ok to take the average score of 10 items?
KevinM2019's user avatar
1 vote
1 answer
211 views

Low internal consistency

I am currently analyzing 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 ...
user241842's user avatar
1 vote
1 answer
204 views

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 ...
Carlos Flores V_'s user avatar
2 votes
1 answer
12k views

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 ...
Adam's user avatar
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