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Questions tagged [centering]

Centering involves subtracting the overall sample mean score from the original score; standardizing does the same followed by dividing by the overall sample standard deviation.

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Fixed-effects using demeaned data: Why are the demeaned predictions different from original data w/ fixed effects?

I'm hoping someone can help me understand why a fit regression model making predictions on panel data with group fixed-effects, outputs different results than the same model predicting on the same ...
hayfreed's user avatar
2 votes
1 answer
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Centering Variables in Multilevel Models with Longitudinal Data

Enders and Tofighi 2007 provide a discussion on the various ways users can center variables in multilevel models and when each situation is appropriate. While they largely focus their commentary on ...
Brian Lookabaugh's user avatar
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Which Variables Should Be Centered in a Multilevel Model?

When only one variable in a multilevel model is of interest (all of the other variables are treated as nuisance parameters), and we wish to estimate between- and within-effects, should we only center ...
Brian Lookabaugh's user avatar
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1 answer
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Equivalence of Fixed Effects in Contextual Models with and without Random Slopes

When estimating "contextual models" (i.e., models that contain level-1 predictors as well as their cluster means on level-2), the estimation of the fixed effects should be unaffected by the ...
abeeisnotabug's user avatar
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Centering two level-1 variables to create interaction term before multilevel analyses? Thank you [duplicate]

I like to ask for some kind help from the readers here. I have a specific question on creating the interaction term from two level-1 variables before even running the multilevel analyses. Do you mean-...
Jomel NG's user avatar
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Controlling for multilevel structure CLPM

I want to run an CLPM and have some questions regarding the clustered structure (school classes) of my data. I learned that centering can account for the nested data structure, but it is only ...
Thomas3010's user avatar
1 vote
1 answer
64 views

Why does centering predictors resolve non-convergence in lme4?

I run quite a few mixed models in lme4. I've found that fairly often models don't converge unless the predictors are centered. I found online that convergence warnings can sometimes be resolved by ...
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Interpretation of logistic regression slope

I am running a logistic mixed model with a binary outcome (correct/incorrect). I have two fixed effect predictors: Condition (0, ‘low’ vs 1, ‘high) Sumspq (a continuous questionnaire score) There is ...
SilvaC's user avatar
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Interpreting intercept with centered predictors in logistic mixed model

I am running a logistic mixed model in lme4. The model is as follows ...
SilvaC's user avatar
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1 answer
220 views

Centering variables in Lavaan - Path analysis

I hope you're doing well. I'm currently knee-deep in path analysis using the lavaan package for my research. My analysis involves moderation, and centering the variables may simplify coefficient ...
Ronald Bahamondes-Álvarez 's user avatar
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Methodology for Analyzing the GAP Between Provinces: Using Derived Variables and Considerations on Fixed Effects Regression

I have a panel data for 106 provinces and 10 year. I want to use a new variable created from the difference of any observation with the mean of the top 10 provinces (highest value), year by year. It ...
Lorenzo Fabiani's user avatar
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Show: scaling transformation $Y_i=D^{-1}(X_i-\bar{X})$ can be written as $Y = HX_{n\times p}D^{-1}$

Show that the scaling transformation $\textbf{y}_i=D^{-1}(\textbf{x}_i-\bar{\textbf{x}})$ can be written as $Y = HX_{n\times p}D^{-1}$ where $H$ is the centering matrix $(I_n-\frac{1}{n}\textbf{11}')$....
reyna's user avatar
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3 answers
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How to decorrelate $X$ and $X^3$?

We know that if $X$ is positive, then $X^2$ is highly positively correlated with $X$. I've plotted an array of integer numbers from 100 and 110 with the following code: ...
ricber's user avatar
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Centering a skewed predictor variable in a multilevel model that is involved in an 2-way interaction

Is there a correct method to center (mean or median centering) a skewed predictor variable in a multilevel model? The predictor is a skewed, count variable and will feature in a two-way interaction ...
ReadBeard's user avatar
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Within-subject mean centering of covariate in linear mixed models

I have a within-subject repeated measures dataset where participants were asked to rate images (48 items) at 3 separate time points (t0,t1,t2). Their ratings at t0 is what is defined as baseline, as ...
sinandrei's user avatar
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About centering to accommodate multicollinearity (Ordinal Logistic Regression Analysis, Logistic Regression Analysis)

When interaction terms are used in multiple regression analysis, often centralization of the variables (subtracting the mean of the variable from each variable) is used to deal with multicollinearity, ...
946's user avatar
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Scaling variables for model selection. Unscaling for final model?

I struggle with the following question: I had to scale variables for model selection as they were in very different units and the model struggled to converge. Now that I have a final model the ...
Norpantytär's user avatar
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Mean-centerinfg for logit values?

I have a question regarding the logistic growth model. Can proportion values that have been converted into logit be mean-centered? When we calculate the actual difference value between two proportion ...
Roy Kang's user avatar
5 votes
1 answer
309 views

Does mean centering work only for normally distributed variables?

In econometric analysis in some cases, such as models with interaction terms, multicollinearity between independent variables may exist. In such cases, some researchers suggest "mean-centering&...
Sane's user avatar
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2 votes
1 answer
147 views

Interpreting interaction between a categorical and centered continuous variable (binary response)

In my model, in which I'm attempting to infer which covariates affect whether a fish has an empty stomach or not (1=empty, 0=not empty), I decided to grand-mean center the variable "SL" (...
Nate's user avatar
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Is Centering Data Around Their Medians in Least Absolute Deviation Regression Model (No Intercept), a Good Robust Practice For Smaller Data Sets?

Per the regression model: $\mathbf{y} = f(\mathbf{x},\mathbf{\beta}) + \mathbf{\epsilon}$ Where the $\beta$ estimate of LAD regression is given by: $ \hat{\beta}_{LAD} = \text{argmin}_{ b} \sum_{i=1}^...
AJKOER's user avatar
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1 vote
1 answer
116 views

Regression analysis with constant dependent variable

Can someone explain to me what's going on in the following? Suppose we have data with constant dependent variable: ...
4twobi's user avatar
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2 votes
0 answers
75 views

Which method to use to scale/mean center a time-varying covariate in latent growth models (SEM)?

I have longitudinal data across several time points. At each time point, participants completed an online test up to 3 times (i.e., measurements were completed 1-3 times at each timepoint). The number ...
AEP_Psych's user avatar
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3 votes
1 answer
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Dropping a hierarchical linear model intercept when centering the outcome at 0?

Suppose a hierarchical linear model with "random intercepts" $\mu_i$ fit to some raw (unscaled) data: $$y_i \sim N(\mu_0 + \mu_i, \sigma) \\ \mu_i \sim N(0,\sigma)$$ If I rescale $y_i$ by ...
socialscientist's user avatar
1 vote
1 answer
183 views

Centering variables involved in an interaction changed results, how is this correctly interpreted?

In my model, some potentially confounding continuous variables had to be taken in account as well as an interaction of this variable with the main factor of interest, which is categorical. Initially, ...
Jobbe Goossens's user avatar
7 votes
1 answer
481 views

Why does mean-centering in a univariate logistic regression change p-values?

I have a very simple logistic model with a single continuous independent variable and a two-category dependent variable. When I mean-center the IV, the p-value of the coefficient changes significantly,...
lua's user avatar
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1 vote
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Is there a "proper" way to keep strictly nonnegative data nonnegative when performing PCA, despite centering?

I have a question that came up in my research and I would really appreciate some guidance from someone wise in the ways of dimensionality reduction. I have a dataset of matrices that are strictly ...
Sam Berry's user avatar
1 vote
1 answer
62 views

How does center variable help address multicollinearity problems for interaction with polynomial terms

I hope someone can help me better understand how center variables can help address the problem of multicollinearity problem when the regression includes interactions with polynomial terms. My ...
zjppdozen's user avatar
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2 votes
1 answer
79 views

How do we report a regression with categorical * continouns interaction?

I was wondering how would be the best way to report this model ? ...
Larissa Cury's user avatar
3 votes
2 answers
952 views

What does "1-unit change" mean when centering predictors in regression?

I know that when we standardize a predictor, "one unit change" becomes one standard deviation in the predictor, but what if we only center the data on the mean (i.e. only subtract all values ...
Larissa Cury's user avatar
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1 answer
85 views

Both quadratic and linear term are insignificant

I am trying to fit a model which has age as a control variable and mental health score as my dependent variable. I centered the age because 0 is not meaningful in my analysis. I tried age, age^2, log(...
Elsie's user avatar
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1 vote
2 answers
186 views

How to obtain uncentered factor scores from Factor analysis

The Exploratory Factor Analysis has the following mathematical formulation as in the screenshot from wikipedia (https://en.wikipedia.org/wiki/Factor_analysis): That means the factors in F are ...
gnm's user avatar
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0 answers
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Centering predictors in linear mixed effects and explaining three-way interactions with continuous variables [duplicate]

I am working on a Linear Mixed Effects model. All four predictors are continuous variables. Full model: ...
Ann Li's user avatar
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0 answers
209 views

centering issue in the multilevel modeling

I learned that categorical variable should be centered just like continuous variable. I am analyzing two level model, (MLM). case 1. when the categorical variable is level 1 predictor, and have ...
yoo 's user avatar
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0 answers
265 views

Mahalanobis vs centering / standard deviations

Is there a difference whether to use a Mahalanobis distance or transform the data via centering (and normalization) when you are interested in calculating distances? This means, if you are interested ...
Ben's user avatar
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0 answers
185 views

What does it mean if we use eigenvetor matrix of centered matrix $\mathbf{X}$ to reduce the dimension of $\mathbf{X}$ without centering?

Recently, I was trying to use PCA to reduce the dimension of matrix $\mathbf{X}$. Suppose a data matrix $\mathbf{X}\in \mathbb{C}^{M\times N}$, where $M$ is the number of variables and $N$ is the ...
tyrela's user avatar
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2 votes
1 answer
654 views

"Group mean centering" a dummy Variable in R for multilevel analysis: how can i do this?

have somebody an idea of how to group mean center a dummy Level 1 predictor in R? Enders & Tofighi (2007) describe a method to center a dummy variable through substracting the proportion of the ...
JoBen's user avatar
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0 answers
306 views

PCA whitening and centering in inference/test samples

[cross-posted from SO] I'm working on speaker identification. I need to take the speaker embeddings from a neural network and apply a few transformations to finally generate the score for verification....
Zabir Al Nazi's user avatar
1 vote
1 answer
677 views

Centering variables that use Likert scales..?

I'm running a moderation analysis, and I was taught that you should center all continuous independent variables. In my department, professors usually treat variables that use Likert scales as ...
user54687's user avatar
3 votes
1 answer
233 views

How does group mean centering affect the interpretation of coefficients in a hierarchical model?

I've dived deeply into the literature, but still don't understand if it's necessary to group-mean center my predictors if I'm entering them into a hierarchical model. Surely, if they're being entered ...
Jeremiah Johnson's user avatar
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0 answers
15 views

original mean from centered array

Given the mean-centered array a <- c(-2.25,0.75,-1.25,2.75,-0.25,1.75,-0.25,-1.25) is it possible to retrieve the mean of the original array used to center it ...
locus's user avatar
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1 vote
0 answers
338 views

When is ok not to centre the data before using it in PCA?

I want to find out if it is ok not to center the data in a PCA when working with stock returns. Centering would remove the trend from the dataset which I believe contains valuable information. The ...
Quipz's user avatar
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0 votes
1 answer
120 views

Can I GROUPMEAN center one variable and not the second one involved in an interaction / Multilevel Model with L1 Moderation

I'm fitting a multilevel model with an L1 moderation on Mplus. I am trying to demonstrate that the effect of X (independent variable / mean of scale items) on Y holds only when people do not make a ...
MEM's user avatar
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1 vote
0 answers
105 views

Cosine similarity with recentering - collaborative filtering

I don’t know much about stats (nor maths), so I’m sorry if I’m not being very clear on this... I’m trying to build a simple recommender system for books using collaborative filtering item by item. I’...
OneMinute's user avatar
1 vote
0 answers
17 views

Problems with 0s when centering a dummy variable within cluster

Supposing that I have a set of data that is structured like this: customerID orderID couponUse purchaseQuantity 1 1a 1 3 1 1b 0 1 1 1c 0 1 2 2a 1 5 2 2b 1 2 3 3a 1 6 3 3b 1 3 3 3c 1 7 3 3d 1 ...
PickledXu's user avatar
1 vote
1 answer
223 views

Centring in three levels multilevel models with cross-level interaction

I am relatively new to multi-level models subject and find it challenging to connect theory to modelling. My interest is to examine the moderation influence of green space (at level 3) on the ...
AhmadMkhatib's user avatar
1 vote
0 answers
353 views

Linear Mixed Effects - degenerate Hessian with 1 negative eigenvalue

I am using linear mixed effects to look at how the variable Neuro (measured at baseline only) predicts change over time in the variable Score (measured at baseline, visit 2 and for some participants ...
Monika Grigorova's user avatar
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0 answers
220 views

Group centering for interactions with within-between mixed panel model

I need to update a model to incorporate an interaction between a time-invariant categorical variable and a demeaned time-variant variable. I'm unsure about how to correctly use group-mean centering ...
dcoy's user avatar
  • 362
4 votes
1 answer
204 views

Why does centering variable A influence my p values of factor B in the linear mixed effects model?

I have a dataset, where I would like to see whether there is a group difference in the measurement "concentration". I have repeated measurements for some subjects, which is why I use a mixed-...
CST's user avatar
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1 vote
0 answers
31 views

Whats the motivation to demean variables when estimating an interaction effect? [duplicate]

I am trying to estimate a regression model where I am interested in the effect of a certain magnitude, probability and expected value (probability * magnitude ) on reaction times. I was told that it ...
Laurie's user avatar
  • 319