Statistical Analysis Stack Exchange
Statistical Analysis Stack Exchange

Questions tagged [scale-construction]

Construction of a measuring scale for a "trait" as a sum (or other function) of individual variables ("items"). Various methods to validate the construction exist (including factor analysis, external criterion, experts opinion etc.).

31 questions
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Creating a single index from several principal components or factors retained from PCA/FA

I am using Principal Component Analysis (PCA) to create an index required for my research. My question is how I should create a single index by using the retained principal components calculated through PCA. For instance, I decided to retain 3…
user179313
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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?
lf_araujo
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Validating questionnaires

I am designing a questionnaire for my dissertation. I am in the process of validating the questionnaire I have applied a Cronbach's alpha test to the initial sample group. The responses to the questionnaire are on a Likert scale; can anyone…
john hall
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What is the relationship between scale reliability measures (Cronbach's alpha etc.) and component/factor loadings?

Let's say I have a dataset with scores on a bunch of questionnaire items, which are theoretically comprised of a smaller number of scales, like in psychology research. I know a common approach here is to check the reliability of the scales using…
adb
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Validation of a questionnaire in a new population

I have 400 responses to a 20 item questionnaire which purports to measure an attitudinal constuct in medical students. The instrument was validated in the US for a single year of medical students and the published data is very "clean"- all ritc…
suzi
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How to do exploratory factor analysis in a repeated measure design?

In my experiment participants answered to the same scale twice, after the presentation of two different stimuli, i.e., repeated measures design. The scale validation is not the main focus of my study, but since the scale is new, I would like to run…
Silvia
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When is appropriate to run a factor analysis at items level vs. scale level in a questionnaire?

I am doing a research validating a new questionnaire, which has 156 items divided up in 12 scales. I have run a factor analysis at scale level, which gives me two nice constructs (consistent with theory). My tutor however is insisting this is no…
Linda
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Item analysis for a likert-type questionnaire - item discrimination, point-biserial, factor analysis, cronbach's alpha, other diagnostics?

I'm working on a questionnaire that is intended to measure two constructs. There are presently 26 items in the questionnaire -- eleven for construct 1 and 15 for construct 2 -- and each item has five available responses: "strongly disagree"…
dubhousing
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Item response theory vs. summative Likert scale

If the items to be "summed" or combined to create an overall index are collectively the underlying construct (i.e. I am trying to measure compliance to an intervention which has different components), wouldn't combining all the components for IRT…
oncearunner
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Scales correlate negatively, but average correlates positively!

I have a total relationship quality variable constructed as the mean of three other scales. Each of these three (family, friend, and spouse) scales is significantly negatively associated with an outcome in a simple regression; however, when I…
Benji
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Using a constructed scale and an individual component of that scale in a statistical model

I am working with a colleague who wants to include a term in our linear mixed effect model that is also an individual component of a scale that we constructed and have in our model (both as predictors). For example, it's something like this: d1 <-…
Burt Macklin
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Equation for weighted average with normalization(?)

I am trying to understand how I should denote the equation for rescaling the following 7 categories into one value. The final weighted average is 0.57, which is possible by subtracting one and dividing by six. At least, this is normalizing…
Marc
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item response theory - criteria for selecting items

I'm trying to use IRT to select the best items for a one-factor scale that has 20 items. I was wondering what I need to be looking at if I wanted to select 5 or so items from these items (for a short version of the scale). I would really appreciate…
llbia
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Why/when do attitudinal scales introduce endogeneity?

I use an example to illustrate my question. I have a model that explains choice of low fat vs full fat milk, that was actually bought in a store. We model it with a binary logistic regression. The model parameters mostly stem from a questionnaire,…
canIchangethis
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How to test for unidimensionality using the mirt r-package?

As it is my understanding that the ltm-package is obsolete, I'm looking for an equivalent to ltm::unidimTest() in the mirt-package. I'm quite new to IRT-Models, so I would be thankful if someone could give me a short breakdown on how to test…
Comfort Eagle
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