Questions tagged [scales]

Scales used to express measurements. Usually ratio, interval, ordinal or nominal types of scales are recognized. Dichotomous and count types are sometimes seen as their own. Other classifications exist. [For "scale" as a sum of individual items in psychometry - see also tag 'psychometrics'.]

See the original article:

Stevens, S. S. (1946). On the theory of scales of measurement. Science, 103(2684), 677-680. [PDF].

For modern criticism, a good place to begin is:

Velleman, P. F., & Wilkinson, L. Nominal, ordinal, interval, and ratio typologies are misleading. [PDF]

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Under what conditions should Likert scales be used as ordinal or interval data?

Many studies in the social sciences use Likert scales. When is it appropriate to use Likert data as ordinal and when is it appropriate to use it as interval data?
A Lion
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scale a number between a range

I have been trying to achieve a system which can scale a number down and in between two ranges. I have been stuck with the mathematical part of it. What im thinking is lets say number 200 to be normalized so it falls between a range lets say 0 to…
Saneesh B
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Normalization vs. scaling

What is the difference between data 'Normalization' and data 'Scaling'? Till now I thought both terms refers to same process but now I realize there is something more that I don't know/understand. Also if there is a difference between Normalization…
d.putto
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Changing the scale of a variable to 0-100

I have constructed a social capital index using PCA technique. This index comprises values both positive and negative. I want to transform / convert this index to 0-100 scale to make it easy to interpret. Please suggest me an easiest way to do so.
Sohail Akram
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When should I apply feature scaling for my data

I had a discussion with a colleague and we started to wonder, when should one apply feature normalization / scaling to the data? Let's say we have a set of features with some of the features having a very broad range of values and some features…
jjepsuomi
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Group differences on a five point Likert item

Following on from this question : Imagine that you want to test for differences in central tendency between two groups (e.g., males and females) on a 5-point Likert item (e.g., satisfaction with life: Dissatisfied to Satisfied). I think a t-test…
Jeromy Anglim
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Visualizing Likert Item Response Data

What are good ways to visualize set of Likert responses? For example, a set of items inquiring about the importance of X to one's decisions about A, B, C, D, E, F & G? Is there something better than stacked bar charts? What should be done with…
alex hoffman
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Whether to use structural equation modelling to analyse observational studies in psychology

I've noticed this issue coming up a lot in statistical consulting settings and i was keen to get your thoughts. Context I often speak to research students that have conducted a study approximately as follows: Observational study Sample size might be…
Jeromy Anglim
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Weight a rating system to favor items rated highly by more people over items rated highly by fewer people?

Thanks in advance for bearing with me, I am not a statistician of any kind and don't know how to describe what I'm imagining, so Google isn't helping me here... I'm including a rating system in a web application I'm working on. Each user can rate…
Andrew
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How to scale new observations for making predictions when the model was fitted with scaled data?

I understand the concept of scaling the data matrix to use in a linear regression model. For example, in R you could use: scaled.data <- scale(data, scale=TRUE) My only question is, for new observations for which I want to predict the output values,…
SamuelNLP
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Factor analysis of questionnaires composed of Likert items

I used to analyse items from a psychometric point of view. But now I am trying to analyse other types of questions on motivation and other topics. These questions are all on Likert scales. My initial thought was to use factor analysis, because the…
pbneau
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Assessing reliability of a questionnaire: dimensionality, problematic items, and whether to use alpha, lambda6 or some other index?

I am analyzing scores given by participants attending an experiment. I want to estimate the reliability of my questionnaire which is composed of 6 items aimed at estimating the attitude of the participants towards a product. I computed Cronbach's…
giovanna
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Sum of rating scores vs estimated factor scores?

I'd be interested to receive suggestions about when to use " factor scores " over plain sum of scores when constructing scales. I.e. "Refined" over "non-refined" methods of scoring a factor. From DiStefano et al. (2009) , emphasis added: There are…
Eric Green
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How to compute correlation between/within groups of variables?

I have a matrix of 1000 observations and 50 variables each measured on a 5-point scale. These variables are organized into groups, but there aren't an equal number of variables in each group. I'd like to calculate two types of correlations:…
blep
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Item Analysis for an R newbie

I am trying to assess a 20-item multliple choice test. I want to perform an item analysis such as can be found in this example . So for each question I want the P-value and the correlation with the total, and the distribution of the options…
Matthew Leingang
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