Psychometrics has evolved as a subfield of psychology to become the science of measurement of unobservable individual characteristics.

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4 views

comparing SEM in Z and T scores

I have a function that gives me the SEM of my test for different thetas. This - I believe - is a SEM of Z scores. ...
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13 views

how to remove outliers prior to multiple imputation

A colleague came to me with the following problem. She has a complex, multivariate data set, in which respondents completed a number of measures with anywhere from 6 to 30 Likert type items for each ...
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6 views

How to calculate discrimination index and difficulty index of short answer test items?

How to calculate discrimination index and difficulty index of short answer test items? Should I use t test or the formula upper group score - lower group score divided by number of students in a ...
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17 views

Select and weigh questions on a reading assessment

I am a phd student in computer science and as such I am the goto guy for anything "mathy" in the cross discipline research group to which I belong. I have recently been given an assignment at work I'm ...
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5 views

Inter-raters reliability for sentiment analysis lexicon

I have a list of words (more than 2000) which were rated by 4 raters for sentiments like anger (scale from 1 to 5). I run an alpha test on SPSS which gives me a coefficient of >8 which shows a good ...
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6 views

What is the two alternative forced choice paradigm

Can someone please help me, Is a two alternative forced choice paradigm (2AFC) an experimental design?
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1answer
33 views

raising the probability of correct answers of nextItem (catR)

Using the catR package I am trying to create a nextItem call that respondents would answer correctly about 65% of the time (even if that means the method is not as efficient as it could be). Children ...
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14 views

Test-retest reliability

I have come across following table in a publication, where r is correlation coefficient. I could not find detailed procedures for test-retest reliability, is it any different from paired t-test ? ...
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16 views

Calculate within and between group correlation

MY DATA: A surveys which contains 2 different questionnaires on the same subject which were taken by n=800 patients (i.e., timepoint) (#1 questionnaire: 5 questions which reach a total score of 0-42, ...
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20 views

Statistical Method for Normalization of Data

I collected data using a pre-test instrument to capture baseline emotions (two dimensions: valence and arousal) of participants. The two dimensions in the questionnaire range from calm to excited ...
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16 views

Comparing confirmatory factor analysis models with different number of observed variables

I have a 14 item scale that is hypothesized to measure self-esteem. The first model I specify uses all 14 items and predicts one latent factor (i.e., self-esteem). I would then like to specify a ...
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1answer
42 views

What is the difference between formative and reflective measurement models?

Can anyone provide examples as to why choose one over the other? Are they calculated diferently?
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16 views

CFA model with systematic temporal correlation between measures

I'm looking to fit CFA models to data in the case where measures have systematic temporal correlations between them. I'm familiar with autoregressive approaches, such as those described on Dave ...
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1answer
41 views

Non-Significant difference between individual items, but significant difference between overall scores

Say that we have a scale measuring Healthiness of Diet, and want to see if two populations have different levels of Healthiness of Diet. If we find that the difference between the two samples at the ...
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3answers
223 views

Is it always better to extract more factors when they exist?

Unlike principal components analysis, the solutions to factor analysis models are not necessarily nested. That is, the loadings (for example) for the first factor won't necessarily be identical when ...
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1answer
67 views

Detecting Differential Item Functioning (DIF) using ordered logistic regression

I am in a situation in which I want to investigate whether test items of a questionnaire appear to have DIF. The items are polytomous and ranges from 1 to 5, with 5 being the most positive answer. ...
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23 views

What measure of test reliability is appropriate if the final test output is not the sum of item scores?

I would like to compute a measure of reliability in the sense of Cronbach's alpha, McDonalds omega or glb. However it seems to me that all these measures assume that the final test score equates to ...
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1answer
56 views

Is empirical reliability in IRT the counterpart of internal consistency in CTT?

In IRT it is not meaningful to compute internal consistency coefficients such as Cronbachs alpha, because standard error of measurement (and thus measurement precision) is not assumed uniform across ...
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41 views

Acceptable values for discrimination parameter - 2PL IRT Model

What is the acceptable range for discrimination parameters with the two-parameter IRT model? I have information from Baker (2001) but would love additional information. I have heard discrimination ...
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51 views

What does 'downward pressure on sample size' mean?

In this article, there is this phrase 'downward pressure on sample size'. This is the paragraph: no matter the approach to collecting this new data, when attempting to ...
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40 views

How can Bayesian inference improve upon logistic regression in incorporating psychometric data?

In order to estimate probability of default, banks and other financial institutions have often used logistic regression based on data involving credit history. Suppose an entrepreneur or borrower ...
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12 views

Combining different measures from different studies

I'm interested in combining outcomes from different psychiatric studies. However, the studies look at different types of diagnoses, that are measured sometimes with the same measurement, and sometimes ...
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1answer
92 views

What is Cronbach's Alpha intuitively?

I'm trying to understand Cronbach's Alpha intuitively. What is the general idea behind this construct? What properties were they trying to ensure that it had?
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25 views

Inter-rater agreement of a gold standard dataset - a ceiling for reliable evaluation of algorithms?

In my field, a dated gold standard dataset is used to track progress in algorithm development. Now when the state-of-the-art algorithms obtain higher correlation than is the inter-rater agreement of ...
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1answer
23 views

Can the test information function be used for a field test item bank?

I am field testing a few forms of items (with embedded anchor items) and will be analyzing the items using IRT, a 2PL model. These items will likely be used to create an item bank that can then create ...
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50 views

What do I do when my second order CFA model is not identified?

I am assessing a measurement model of a three-factor organisational commitment scale for my PhD project. Although congeneric single factor and first order CFA models have produced excellent model fit ...
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1answer
24 views

measure development - removing items from an item pool due to ceiling effect

During the early stages of scale development, many items within our item pool were found to have a strong ceiling effect with low score variability. In order to attempt create a meaningful measure ...
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3answers
192 views

“Two stage” factor Analysis: factoring saved factor scores

I have a model which consists of 19 questions, which are divided in three factors (factor 1 - nine questions, factor 2 - six questions, factor 3 - four questions). For this I did a factor analysis and ...
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53 views

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 ...
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2answers
66 views

The valid variance components to include in a generalizability theory model (anova) involving nesting? Are these correct interactions?

My question is about generalizability theory. A study by Bergeron, Floyd, McCormack, and Farmer (2008) is only adding to this confusion. Basically, in G-theory you want the first model you run to ...
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160 views

Interpreting summary of ICC results in R package “psych”

I have a dataframe "all.st.icc", where 27 subjects have measures of social behavior for each of 8 different years. First four rows of data are as follows: ...
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54 views

Is the use of PCA appropriate to validate a designed questionnaire?

I looked at the questions that may already have my answer but unfortunately it is not the case. I would like to ask again my question which has been revised to fit the rules. I am to measure 5 ...
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20 views

The differences between criterion validity and operational validity

In some psychological articles, I have seen the term "operational validity". It is often used instead of "criterion validity". What are the differences between these two concepts?
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65 views

Attitude measurement – Score classification – Why using percentiles?

Once we have raw scores from a group of Likert scale items, why are percentiles used instead of considering all the possible scores from the total number items when classifying results of individuals ...
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40 views

Combining different raters scores

In my experiment two raters evaluate 100 products, both expressing an "innovation score" on a likert scale (range is 1 to 5, where 1 is "not innovative" and 5 is "disruptive innovation"). I ...
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53 views

Which CFA model is the best fit in my translation & validation study?

I have translated and adapted a questionnaire (based on a 5 factor model; 23 items) into my native language by following ITC and MAPI guidelines. Forward / backward translation, expert panel review, ...
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1answer
65 views

Questions regarding interpretation of item parameters: inconsistent results between classical item analysis and item response analysis

I was not trained as a psychometrician, so my questions may be concept-related. If you know different resources, books, or articles that can clear my confusions, please let me know. Thank you very ...
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1answer
35 views

Where I can find resources to learn how to calculate the sample size representativeness, and realiability and validity of questionnaires?

I'm totally newbie in psychometrics but starting from a research paper with full data I would like to understand: how to calculate if the sample size is representative; how to calculate reliability ...
3
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1answer
108 views

Is it possible to do IRT distractor analysis using R?

I've been using the mirt package to analyse a few response matrixes I have through IRT. However, every time I need to perform distractor analysis, I end up having ...
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1answer
219 views

Questions Regarding Item Response Models – the 3PL model vs. the mixture of 2PL and 3PL model

I currently work on an item analysis for an assessment. The assessment consists of 25 multiple-choice questions. Each question has 4 choices with one correct answer. I used different IRT models to ...
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20 views

Correction of data using a correlation

Suppose I have measured the outcome variable A using a (psychophysical) test that determines the ability of a subject to discriminate between two stimuli with a certain difference (the variable X). It ...
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1answer
88 views

Item discrimination of poorly targeted items

In test theory, it appears to be widely recognized that very "easy" or "very difficult" items, relative to the ability of the sample of respondents, will have deflated correlations with the rest of ...
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1answer
28 views

An invalid questionnare with valid resultant scores?

In what situation, a questionnaire could be invalid but its resultant scores could be valid? I received a comment from a journal article reviewer that says: In keeping with the preferred ...
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26 views

Is there any research that compares Likert scale questions to “satisfaction” scale questions?

I'm trying to put together a questionnaire for measuring employee satisfaction with an internal process. I'd like to figure out if there is reason to prefer: ...
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29 views

Is a representative sample necessary to assess construct validity?

To generalize results to a greater population, a representative sample is necessary. In developing a psychometrically valid instrument, via confirmatory factor analysis or item response theory, we are ...
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2answers
175 views

What is a good method to identify outliers in exam data?

I give my students an exam that has 8 questions on it. Each question is about a particular topic. The exam is made up on the fly by randomly selecting 1 question for each topic from a pool of ...
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49 views

How to build a perceptual scale using ratio measurements?

I have several physical samples of a material that vary according to some physical measure, e.g. hardness, roughness, brightness etc. Let's use brightness as the example. Now, I am not so much ...
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269 views

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 ...
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1answer
375 views

What is the statistic to calculate Cronbach's alpha for Polytomous items in R

Does anyone know, what is the function which can calculate Cronbach's alpha for polytomous items with different categories in R? Thank you
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1answer
39 views

Reading recommendations for psychometric refinement

a research project turned up a large number of survey instruments on a specific topic. There is a great deal of conceptual item overlap in these instruments, but they do differ in some key ways, ...