Questions tagged [repeated-measures]
Repeated measures data occur when more than one measurement is collected on the same units (e.g. subjects). Use this tag for RM-ANOVA together with [anova] tag.
2,827 questions
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Is a linear mixed-effects model appropriate with only one observation per task per participant and n=13 per condition
I am analysing data from a pilot VR study with a between-subjects manipulation of arousal (High, Neutral, Low), with 13 participants in each condition. Each participant completed three different VR ...
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Should I use glmer or glmmTMB (family = gamma (link= "log") for repeated measures experiment?
For my experiment, I exposed fish to one of two treatments (n = 10 per treatment) and repeatedly measured their metabolic rate at seven different timepoints. Unfortunately, at the last time point, ...
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What structure of mixed model should be used for experimental repeated measures data like this?
Background
I have data in a similar form to that described in this question: What statistical test(s) should I use for this kind of repeated measures data?
The answers to that question suggested some ...
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Statistical analysis for a within-subjects design with a randomly varying factor
I have a statistics/data analysis question. I am conducting a study in which participants view and rate how much they like different pictures. I am interested in several within-subjects factors. Each ...
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Why are estimated marginal means from a linear mixed / multilevel model and Mixed ANOVA different?
I have trouble understanding the causes of differences in estimated marginal means derived from a multilevel model and from a mixed ANOVA, in particular in a case with only two time points and a ...
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Repeated Measures model vs ANCOVA a model for a between subject pre post experimental design
We have a between subject randomized treatment $T_i$ for individual $i \ldots N$. There is a pre and post outcome $Y_{ij}$ for time points $j = [0,1]$. $T_i$ is a dummy variable equals 1 when subject $...
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Ordinal response, two groups, repeated measures
I have an ordinal dependent variable and a dichotomous independent variable (group: A or B). The response has 4 levels and is measured multiple times on the same subjects. Data looks like this:
...
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Which statistical analysis to compare methods between different locations?
In four different locations (L1, L2, L3, L4), I have conducted measurement of gas fluxes, and used different methods to estimate fluxes (M1, M2, M3). In each location I have 10 chambers to collect gas ...
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Test of independence between two ordinal variables with repeated measures
I have two ordinal variables: $Y$ and $X$. Variable $Y$ has 4 levels, variable $X$ has 3 levels. These variables are measured multiple times on the same subjects. Data looks like this:
subject
Y
X
...
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Modelling profile over time when changing start point
I have data in JMP which is formatted with columns (simplified):
Sample name
Initial value
Value after 4 weeks
Value after 8 weeks
Value after 12 weeks
I have 200+ rows
My aim is to model all of ...
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Repeated-measures ANOVA vs repeated-measures ANCOVA: what’s the difference?
I’m analyzing a pre–post design (two time points: T0, T1) repeated-measures design with one between-subjects factor (Group) and two participant-level covariates that are constant over time (Age: ...
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What statistical test to use for A/B test data (dichotomous) with repeated measures
This is my first time doing an A/B study with repeated measures, and I'm not sure the appropriate method for analysis- typically, I start with a one-sample proportion test, but obviously my data ...
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post hoc tests after running repeated measures ANOVA
If we apply a repeated measures ANOVA, does that mean the post hoc tests must be based on paired t-tests and cannot use nonparametric tests?
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Extending Andersen-Gill model with (part of) event history as covariate
In the counting process interpretation of the cox model for time to event with hazard $\lambda$, we have:
\begin{equation}
\lambda(t\,|\,Z(t))=\lambda_0(t)\exp(\beta^*Z(t)),
\end{equation}
where $Z(t)...
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comparing factors between groups depending on another factors that is missing in one group
I am not sure how to analyze the following problem.
I have two groups of human subjects (same numerosity N=22). One group (patient) was injured on one leg, the other group (healthy control) had no ...
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Repeated measures logistic regression with varying no. explanatory variables for each timestep?
I have a short time series of repeated measures of a binary response variable, with ~250 observations (1 per individual) per year over 3 years. An individual's response can be 1 or 0 in any year ...
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GEE with 2 clustering variables?
Traditional GEE models only have 1 "clustering" variable. For example, suppose I have an outcome that is measured multiple times on each patient. Then "patient id" would be the ...
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Logistic Regression and Independence of Observations. Modeling with Repeated, Overlapping Observations
Modeling with Repeated, Overlapping Observations
I'm trying to build a predictive model, but my dataset has repeated observations for the same entity, which violates the independence assumption of ...
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Longitudinal intervention vs control with nonlinear rise–decay: phase-aware natural cubic spline mixed model?
Design:
18 participants total (12 intervention, 6 control).
Intervention group consumes a nutritional supplement once daily for 5 consecutive days; control group abstains throughout.
Outcomes are ...
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What does the singular vectors in a SVD represent when having repeated measurements in the original data matrix?
I'm wondering if this is correct reasoning:
SVD constructs new orthogonal vectors as linear combinations of the rows and columns in the data. In effect correlation among the original variables are ...
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How to perform repeated measures analysis with left-censored data using Kaplan-Meier in R? [closed]
I am conducting a simulation study involving left-censored continuous data. For each subject, I have repeated measurements at three different time points.]
My goal is to apply Kaplan-Meier estimation ...
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Can a lat/lon covariate replace a random (location) intercept?
I'm interested in modeling the spatial component of my data (counts), but I also have a random intercept for site (repeated measure design, n=47, over 17 years). The area sampled are roughly the same, ...
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Repeated measures, reliability and validity tests
I conducted a pre-test consisting of an experiment in which a sample of 50 participants was exposed to 16 images. While viewing each image, participants responded to a Likert-type fear scale composed ...
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Which technique should I use to test the independence categorical variables over repeated samples
I have individual level data with a performance measure (good/bad) and characteristic variables for the individual (e.g. gender). I usually analyse this using a chi-squared test to see if the ...
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Experiment Design Power Analysis for PhD User Study, Within or Mixed Subjects
I'm designing a user perception study as part of my PhD project, and I'm trying to figure out the sample size I need. I created clips of an avatar talking for 20-30s, and I'm varying the verbal style (...
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Interaction Time with within-individual effect in multilevel models- interpreting positive estimates
I'm running a multilevel model decomposed in between and within values for my predictive variables of perceived uncertainty:
...
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GLM and repeated measures
I am hoping I could get some help to choose the appropriate statistical approach to answer my question.
I am testing 3 different methods to detect birds at night: visual counts (VC), thermal camera (...
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What statistical model is appropriate for a mixed design with ordinal, continuous, and discrete outcomes?
My study is on understanding differences in gender relative to cognitive load and AI usage while coding. My background is not in statistics so I am trying to do the study justice.
2 genders are being ...
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Time trend analysis of blood cadmium in repeated cross-sectional data with changing areas and sample sizes
I’m analyzing blood cadmium (Cd) levels over time using repeated cross-sectional convenience samples collected in four studies:
Study 1 (2007): town A, B, C (n ≈ 150)
Study 2 (2011): town A, D (n ≈ ...
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Multiple imputation of outcome and time-to-event in survival analysis
I have a longitudinal dataset, and I need to use biomarker data (available only at one time point, cross-sectional) collected at the midpoint of the study (e.g., visit 3) to predict incident disease.
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Alternatives to odds ratio (OR) when non-independent observations
I'm working on a medical research project where our main dataset consists of presentations to the hospital over a long period. During this time, a significant number of patients present multiple times,...
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Repeated Measures Mixed Models - Time varying factor
I want to run a repeated measures linear mixed model, but I am new to this, and I need some guidance.
I have a continuos dependent (DV) that was measured across 3 time points. I want to check if my IV ...
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How to assess whether temporal fluctuations in a variable are associated with adverse outcomes?
I am working with longitudinal data containing repeated measurements of variables such as body weight or a cardiovascular risk score. I am interested in evaluating whether within-subject fluctuations ...
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Is a linear mixed-effects model appropriate for repeated-measures data with a small sample size (n = 14)?
I’m analyzing data from a repeated-measures design involving 12 participants. For each subject we measured a continuous dependent variable extracting five different dynamics (Alpha - Beta - Gamma - ...
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is there a way to do a repeated measures ANOVA with nested random effects in R?
Basically the title. I know the anova_test() from the rstatix package can do repeated measures and does have an inclusion for error, but I'm not sure if I'm doing it correctly and I'm not including ...
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Is it valid to use age again as a fixed effect in the model if the outcome already includes it?
I'm modeling a longitudinal risk calculation function using linear mixed-effects models (lme() in R, code below). The outcome is not a raw clinical measure — it's a derived risk score that already ...
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Are there different variations of partial eta-squared for a split-plot ANOVA?
There are two questions for this post:
¿Are there different variations of partial-$\eta^2$ for the between factor of a split-plot ANOVA?
If so, ¿when would you use one or the other?
In brief, when ...
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Why do I need a nested rather than two separate random effect(s) when accounting for pseudoreplication in the presence of repeated measurements?
I have a dataset from individuals, where measurements of different urinary biomarkers have been taken on two study visits:
Subject ID
Value
Visit
Biomarker
Predictors 1-10
1
1.2
1
A
1
1.4
2
A
1
1.5
1
...
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Calculating covariances when there are repeated pair elements
I am calculating the covariances and correlations of parent-offspring pairs with respect to several traits to estimate heritability. In most cases, there is a single offspring per parent, while in ...
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Is mixed modeling a variance reduction technique? And how can I plan an experiment that uses it to reduce variance?
Matched pairs experimental designs (where two "identical" individuals are assigned different treatments) are one technique for (potentially) reducing the variance of a response (relative to ...
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Repeated measures dataset with time based outcome that overlaps (1-year mortality)
I have a dataset which includes multiple hospitalizations of the same patients. For outcomes that occur within the hospital stay, I can use a model that controls for lack of independence, GEE or the ...
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What statistical test to use here?
How to analyse this data?
The percentage of wound closure was determined for 4 different substrates + control group over 4 different time points (18, 24, 48 72 h). Each substrate had 3-4 replicates, ...
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Best way to compare variance between two treatments with repeated measures and uneven samples?
I am trying to determine whether the variation in a response differs between two treatment groups, I am curious what others think of my current strategy and I have some outstanding questions that I ...
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GLMM - Random Effects Not Normally Distributed
Update:
Based on the responses and comments, I don't think I should use the GLMM because my patient ID (random effect) perfectly predicts treatment outcomes. Defining treatment outcome as a predictor ...
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Is the autocorrelation of two measurements just the correlation between measurement 1 and 2?
I have over 100 sites where forest carbon was measured once in 2010 and again in 2020. I want to see if the second measurement is significantly dependent on the first one. I think this might also be ...
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Efficient model/test for treatment effect averaged across several specific timepoints?
In a hypothetical clinical trial, there are four post-baseline time points. If I want to leverage the repeated measures design to maximize the ability to detect a true effect on a noisy outcome, I ...
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Only include a few covariates in a model to answer a single research question, or include many covariates to answer many questions?
I've been following the mixed modelling approach of Dimitris Rizopoulos (link) for a time-series longitudinal dataset of forest carbon simulation bias for many sites.
Here is the process Dimitris ...
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Is there any way to calculate or account for auto-correlation of many samples that each only have 2 observations?
Forest carbon has been measured for over 100 independent sites, and each site has been measured at two time points 10 years apart. At observation 1, each site has an amount of carbon that is ...
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Model selection for fixed effect and crossed random effect structure in glmer
I'm new to (generalized) linear mixed effects models. Any help would be appreciated!
Below is my study design with dummy data. I'm exploring the effects of the parameters I manipulated in game 1 on ...
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Selecting a statistical test method for repeated measurements to determine if there is a trend in the measurements
This is probably a simple question, but...
A city I work with has a retaining wall that shows some cracks in the decorative facing. We can't tell if that is just the facing that needs to be repaired ...
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