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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23 views

Reliability estimation for questionnaire - is Cronbach's a applicable?

I am fairly new to scale analysis and I need to estimate the reliability and validity of a 5 item scale (5 questions, 2 have 4 choices abcd and 3 have 2 choices ab). The scale is supposed to be ...
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Cronbach's alpha for different items?

Can I perform a Cronbach's alpha test when the questions or items are completely different to each other as opposed to having similar questions written differently as a consistency measure?
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Can cronbach alpha be used for multiple choice questionnaires

I am trying to validate a questionnaire. It has four parts - knowledge, perceptions of vitamin D, perceptions of sun exposure and attitudes toward fortified supplements. Can I use cronbach for ...
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first factor saturation vs. general factor saturation

a simple explanation between these two in the context of reliability analysis, specifically Cronbach's alpha.
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31 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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101 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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Difference between Cronbach's alpha and Pearson's coefficient

I am creating an indicator for social development which includes variables of health, education and economy. Since I have many variables, I decided to remove some of them based on dominion expertise ...
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20 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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30 views

Factor analysis

I have a couple of questions on factor analysis using Stata. How to decide whether to use pf (principal factors, default), pcf (principal-components factor), ipf (iterated principal factor) or mle (...
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Analysis for Pilot Test Study Results

Is it possible to use Cronbach Alpha for a preliminary test study that has mostly dichotomous, nominal or ordinal responses or is this analysis method only specific for interval level responses such ...
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How to determine with confidence whether a latent construct is represented by a survey?

I recently reviewed a text designed to evaluate the validity of two surveys of self-care behavior. The authors used principal component analysis and Cronbach's alpha to valuate 2 surveys. Reading ...
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Type I and II errors accounted for by one equation?

On this website: https://clincalc.com/stats/samplesize.aspx both type I and II errors are accounted for by the one equation. Surely, because a type I error involves too much positive variance and a ...
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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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183 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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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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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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144 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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126 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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121 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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360 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
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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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163 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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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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117 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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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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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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101 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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2k 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 ...
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Cronbach alpha application

I developed a questionnaire to measure some factors influence in decision using related literature and after some interviews. Now I have to validate and see how to distribute among the target group. I ...
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2k views

What does it mean if I have high Cronbach alpha, but poor results in Exploratory Factor Analysis

I have been given a survey to analyse. There are 50 questions, and about 400 respondents. I have calculated Cronbach alpha for the entire thing, and I get about 0.9. When I do factor analysis, I do ...
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124 views

How to calculate Cronbach's alpha for instrument that presents every test item twice in an administration?

Background I'm currently trying to calculate a Cronbach's alpha statistic for an instrument that has participants take every item twice during the administration. We are using a speeded mental ...
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2k views

Minimum sample size for Cronbach Alpha?

What should be the minimum number of people in a sample for finding cronbach alpha for: Questtionaire with 20 items (Likert scale) Test with 20 items (multiple choice) A sample of 10, 20 or 40 ? ...
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310 views

Cronbach Alpha for a test to be administered for two different samples

I need to calculate Cronbach's alpha for a test planned to be administered for two different samples. The test is planned to measure knowledge of these two samples, and these two samples vary on the ...
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47 views

When to calculate Cronbach's alpha for a paper?

I am doing my undergraduate thesis, and I wonder if I need to do the Cronbach's alpha from my data set, or if I should use the Cronbach's alpha from the commercial questionnaire I will use for this ...
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R results two different values of Cronbach Alpha

I'm a programmer and I needed to do a Cronbach's alpha method to compute statistics. I tried to write a code but I got two values of alpha: ...
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2answers
2k views

How to do a factor analysis with just one component?

I have done a questionnaire with six questions to measure engagement. This is the only component I measure. To make sure they measure just one component, I tried to run a Factor analysis with Direct ...
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286 views

Calculating Cronbach's alpha for pre-post scales separately or together?

I am measuring a self-efficacy (SE) score by measuring 7 sub-scales for pre and post intervention.For example, for a participant, I have the SE score by measuring 7 sub-scales before the intervention, ...
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129 views

Compute scales/subscales

My dissertation (psychology) is on the relationship between social connectedness and psychological distress. Essentially, I am combining 9 scales that broadly reflect social connectedness (loneliness, ...
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579 views

How to calculate alpha reliability of a scale (factor) when it is expressed in factor scores?

I am doing a Principal Axis Factor Analysis, I found two factors and saved the factor scores for each, using the regression approach (as in the SPSS option by default). My question is, how do I ...
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261 views

Factor analysis and cronbach's alpha

My research work is based on a questionnaire which includes all types of questions ordinal as well as nominal but 80% of the questions are based on likert scale 1-5. My question is whether Cronbach's ...
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22 views

Cronbach's alpha on results from different classes

If 200 students respond to 3 items concerning one construct on a course evaluation, but the students are from 2 different classes within a program, can Cronbach's alpha be used?
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529 views

Cronbach Alpha Testing for tau equivalence

This question is related to a previous question I opened I have a scale I wish to apply Cronbach alpha to. One of the assumptions of Cronbach's is the tau equivalence assumption which according to my ...
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1answer
2k views

Reliability testing for questionnaire with nominal multiple choice questions (one possible answer)

I have used a questionnaire to collect data from 200 people. This questionnaire was obtained from a published research paper in which researchers had used it in a specific population. It involves 34 ...
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51 views

Assess reliability in a pilot study

I'm performing a pilot study in medicine about a new prototype for a diagnostic procedure. The objective of the study is to determine if the prototype is working correctly in order to further develop ...
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Cronbach Alpha VS Composite Reliability: a big difference?

I've read elsewhere that Alpha is probably a low-bound estimate of realibility if the tau equivalence is violated (which is often is). An alternative was proposed which is the composite reliability. ...
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29 views

Reliability/validity required for the mean of combined items?

Let's just say that the 4 items making one construct are not well correlating (for whatever reason) and their Cronbach is 0.62 despite loading into 1 factor. Is there an alternative way to proceed? ...
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PCA with oblimin rotation: should I interpret component matrix, pattern matrix or structure matrix?

I conducted a principal component analysis (PCA) with direct oblimin factor rotation in SPSS. Because by that time I didn't know any better, I used the COMPONENT MATRIX for interpretation. I added ...
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Reliability of research tool with Yes or No answer?

I am doing research on school security. Questionnaire pertains to questions regarding availability or non availability of certain items so as to reach on conclusion that what is available and what is ...