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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Tests for item rating reliability (Cronbach's alpha?)

Here is the situation: I am asking participants to provide some names of a certain category. (Imagine a verbal fluency task where you are asked to name as many animals as you can in the space of 1 ...
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18 views

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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28 views

KMO and Cronbach's Alpha in a multiple regression

I am trying to figure out a reviewer's comments on a manuscript I have submitted. In the paper I fit multiple linear regressions using OLS. The cross-sectional observations are countries. My dependent ...
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20 views

Interpreting low Cronbach's alpha after PCA

I've been running an exploratory analyses on my dataset. I have completed PCA analysis and decided to retain 3 factors. In the subsequent reliability analysis, I discovered that the overall ...
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17 views

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 assess reliability and validity of questionnaire compared to existing questionnaires?

I have a sizeable data set (e.g., 200+) of responses on ordinal scales (e.g., 1-4) for several questionnaires. One of these is newly designed by me. I conducted several questionnaires with the ...
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45 views

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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17 views

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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33 views

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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Should we remove negative Corrected total item correlation variables while doing Cronbach's alpha scale method?

I am having an issue in considering the variables which should either be removed from the model analysis based on their Cronbach's alpha value and what should we do with the variables having negative ...
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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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30 views

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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How to measure internal consistency of 1 person over 3 conditions

I have conducted a survey in which people rate 4 images out of 5, rank 4 images on a scale 1-4 and choose only one image when displayed 2. The results were normalised, so each image for each method ...
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When conducting a reliability test using Cronbach's alpha, is it better to conduct the reliability test on the raw data or the cleaned data?

I'm working on a longitudinal study, and I had to take out some participants who didn't meet the required number of days completed. When conducting a reliability test using Cronbach's alpha, is it ...
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Reliability test

I conducted a survey after which I am analyzing using SPSS, I have a total of 105 data set and 7 variables, but the reliability test gave me a Cronbach's value of 0.21, which is so low. What should I ...
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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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150 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_{...
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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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154 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 ...
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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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1k 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 ...
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106 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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218 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?
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120 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 (...
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2answers
207 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 ...
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392 views

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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27 views

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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231 views

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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2k views

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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67 views

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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7k 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 ...
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7 views

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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1answer
423 views

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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1answer
59 views

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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730 views

Interpreting low Cronbach's alpha value in CATPCA

I ran categorical principal component analysis (CATPCA) on the data that I collected through a questionnaire. The purpose of the questionnaire was to understand pedestrians intentions and attitudes ...
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247 views

What is the point of reporting split-half reliability together with Cronbach's alpha?

In several journal articles I read, autors report split-half reliability (Guttman formula obtained if questionnaire is splited into two parts: odd items and even items, usually) together with Cronbach'...
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2k views

Cronbach's alpha: how many digits to report?

I submitted my first paper to a peer-reviewed journal and got lots of feedback, questions and criticism back. One point was related to the number of digits I report for estimated values (e.g. for ...
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198 views

What is the relation between Cronbach's alpha and pair-wise correlation?

I generate multiple responses using a multivariate normal distribution with means of 5 and standard deviation of 2; I want ten responses and set the correlation between responses to be 0.5. ...
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2answers
487 views

Why does a factor need to be internally consistent?

I'm wondering exactly what the question says: Why does a factor (as linear combination of its items) need to be internally consistent? If I want to use a factor found in a factor analysis as a ...
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1answer
34 views

Psychometric properties on new sample with old questionnaire

When using a decades old inventory, questionnaire or factor from a questionnaire, is it important to retest the psychometric properties of this with the current sample, i.e. compute new Cronbach's ...
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271 views

Correlation between Likert scale independent variables and multiple categorical dependent variables

Based on the above diagram: My alpha for the independent variable is above 0.7 My Alpha is negative for the dependent variable. (I tried reversing items with negative words and the option of if ...
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3k views

Cronbach's alpha -- optimum value is 1.00?

I have been brushing up on some stats and figure I'd have a look at Cronbach's alpha. As I understand it, a higher alpha coefficient means a greater interrelation between all the items. If items are ...
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1answer
262 views

How to combine different type of items of a questionnaire into a variable

I'm doing a research where I applied a questionnaire with 67 items measuring 5 variables. The issue is some questions are in Likert scale (0 to 10 and 1 to 5), some Yes, No, some open questions, ...
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63 views

Varying Likert Scale Categories

I hope that someone can help me with this question. I created a questionnaire that has different scales for each of the questions under one construct. Each of the questions still have a 5 point ...
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36 views

Are reliability and validity measures necessary for all parts of a survey

I am conducting analysis on a questionnaire which was a three-part study, not three separate studies. I asked the same exact set of validated scale questions for specific constructs for three ...
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159 views

do cronbach and factor analysis work together

I am writing a Master's Thesis based on a four construct model. I know I have to conduct a Cronbach's alpha test for reliability and I also need to conduct a confirmatory factor analysis for validity ...
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5k views

Does Cronbach's alpha reveal reliability information over and above the intraclass correlation coefficient?

I have seen in some papers that they have reported ICC as well as Cronbach's alpha. Does Cronbach's alpha provide more information about the reliability of a measured variable (e.g. heart rate at two ...