Tagged Questions

18 views

Chosing the reference group in a regression with a non-ordinal predictor

When running a model with a categorical predictor, the output contains n-1 p.values where n is the number of levels in the factor. One level is taken to be the reference group. For example: I ...
78 views

Ordinal Regression: Proportional Odds Assumption

I'm analyzing survey results with most responses coming in the form of Likert scales. Many of these scales have either very few or 0 responses in the bottom categories. As you can imagine, this is ...
70 views

Testing if treating a categorical variable as continuous is okay

Pardon me if this is a simple question, but I haven't found a great resource for this just yet. Yes, I know that when possible, we should try to treat ordinal variables as categorical rather than ...
87 views

From dummy coding to ordinal variable

I have read from multiple sources (like this pdf) that in a linear regression model, an ordinal variable can be obtained by imposing linear restrictions on its dummy coding. e.g. $x$ is an ordinal ...
51 views

Type of a variable built by binning some numeric variable

I have some sample data with age and I'd like to put them into bins (for example, ranges 20-24 25-30, etc.). The resulting variable would constitute values from 1-8. What I'm confused about is what ...
163 views

How to analyze ordinal repeated measures data

I have data from an ordinal scale, with the score ranging from 1-4. Each subject has 9 assessments on this scale (study is a 9-way crossover design), and there are no missing data. What is the ...
254 views

Pros/Cons of recoding ordinal/nominal variables to target mean for logistic regression?

Say I have an independent variable with the following relationship to the binary dependent variable, DV: ...
31 views

Orthogonal contrast with an ordinal variable in GAM

I am fitting a set of continuous and factor variables into a GAM. The factors are ordinal: they are levels of abundance of specific macroinvertebrates set as "none" (0% cover), "low" (>0-10% cover) ...
67 views

finding the residual variance after correcting ordinal data for sex

I have a data set organized as: males, females as groups. Each individual has a "score" that is ordinal, ranking 0,1, or in another case, 0,1,2. I need to find the residual variation after correcting ...
733 views

I’m using Stata 12.0, and I’ve downloaded the polychoricpca command written by Stas Kolenikov, which I wanted to use with data that includes a mix of categorical ...
397 views

Which logit/probit model do I use for multiple reponse/dependent variables?

I have $300$ time series objects that constitute the $300$ columns of matrix $X$. This matrix has $5$ rows and represents $5$ days of time series information for each $300$ columns. I set up a ...
71 views

Manipulating ordinal variables to segment data

Im working with a negative binomial regression where the dependent variable is number of trips by any given mode (i.e. car trips, train trips etc). I would like to create a variable to segment the ...
42 views

Analysing when tunes are alike: testing ordinal and categorical similarity

I'd like to compare some Jazz tunes. Jazz tunes are characterized by a succession of chords. The interval between each succeeding chord (number of tones) and the order in which they appear matter. ...
3k views

About correlation of ordinal variables having different number of categories and about correlation of mixed type of variables

I have three questions: For data with different response categories (likert type or ordinal) what type of correlation should be calculated? I know for ordinal variables Spearman's rank correlation ...
2k views

Factor analysis for ordinal variables that have different categories

I have a data set that contains about 40 categorical variables that are taken as independent variables (and believed to be related to some unobservable human resource factors) and 4 categorical ...
5k views

How to transform ordinal data from questionnaire into proper interval data?

Are there any straightforward methods of transforming ordinal level data into interval level (just as there are for doing it the other way round)? And performable in Excel or SPSS? Having the data, ...
769 views

How to perform correspondence analysis on ordinal data in SPSS?

I have 500 rows and three columns. Two of the variables (that i want to analyze) are in ordinal form and the other in scale. However, when i run the correspondence analysis wizard in SPSS i can only ...
715 views

More than one outcome (dependent) variables in ordinal logistic regression

I want to run ordinal logistic regression (OLR) in SPSS. My data include 6 predictor variable (two continuous and 4 categorical ) but my outcome variables are also 6 (categorical-likert scale). e.g my ...
643 views

Independent variables in ordinal logistic regression

One of my IV's for my ordinal logistic regression is a nominal categorical variable with 4 categories. Most examples I see for this type of logistic regression have only binary categorical variables. ...