Questions tagged [crossover-study]

A crossover study is an experiment in which subjects are given a series of treatments in succession. Ideally, all orderings of treatments are used with equal numbers of subjects. Crossover studies are common in clinical trials. Carryover effects are a special concern with this design.

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Is it normal when including an interaction effect as a fixed effect in a mixed effect model the p-value of the main effect change drastically?

I conducted a randomized crossover study in which I had two within subject factors; condition and Time. When running a repeated measures ANOVA the analysis shows significant main effect of condition ...
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Does linear mixed-effects models have an advantage for specifically cross-over effects?

I have not read this anywhere but what I think is mixed models have some advantages (against other methods such as ANOVA) for cross-over effects since they treat individuals differences (intercepts) ...
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Crossover study design and statistical method (ANOVA or Linear mixed-effects models)

I have a crossover study dataset. I would like to conduct a linear mixed-effects study. What are the pros of LME models over ANOVA, but, for specifically crossover studies. Thanks in advance!
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Can parallel designs be considered the "gold-standard" for RCTs

Statistically speaking, are parallel designs the "gold-standard" for RCTs? I mean statistically in opposition to financial, ethical or operational aspects. The only drawback I see for (...
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Sample size calculation for a Randomised Controlled Trial

I know the sample size calculations for a Randomised Controlled Clinical Trial for inferiority, superiority and non-inferiority setups. But, say I have a Cross-over Randomised trial design with one ...
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Period effect in crossover design

I am confused with period effect, secular change, temporal trends in crossover design. In this article it is stated that The randomization of the treatment sequence helps to account for temporal ...
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Analysis of a Cross-Over Design with one baseline

My colleagues and I are designing a treatment study using a cross-over design. The subjects are going to be psychiatric inpatients and we want to see wether an exercise intervention has positive ...
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How to calculate number needed to treat for case-crossover study design?

I'm relatively new to epidemiological methods. I'm trying to assess a program where I have access to administrative data that can be put into a case-crossover study design. I'm trying to assess the ...
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How to calculate the effect size in a 3 by 3 crossover design study?

How does one proceed when one want to calculate effect sizes for a 3 by 3 crossover design, in which individuals only have one observation in each period (i.e. no repeated measurement setting)? I ...
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2x2 Crossover Trial - minimum observations to run a linear mixed model

I am planning a 2x2 randomized crossover trial with about 20-25 subjects. There will be one measurement (continuous outcome) with period A (intervention) and period B (placebo) for each individual. ...
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Does a half-crossover design exist?

I've read about incomplete crossover designs, where subjects do not complete all treatments. However, I haven't seen anything about subjects completing all treatments, but not all treatment ...
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Is it possible to verify that washout period was sufficient? And find out if it can be shortened?

Is it possible to use the data collected during the washout period to verify that the length of the period was sufficient? The carryover effect was not significant (we did not expect a carryover ...
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ANOVA Repeated Measures crossover design, number of measurements in GPower?

I am planning an experiment in which I will have a group of animals which I will give both the control diet also test them on the treatment diet. I think I can use repeated measures ANOVA for this. I'...
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I'm lost in Crossover design-repeated measurements and mixed modelling

I am searching for days now, in what I think is a repeated measurements crossover design but I think I got mixed up reading up on it and I'm now going in circles so I was wondering if anyone could ...
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linear mixed model for a simple crossover trial

I would like to understand how to analyse a basic crossover trial using a linear mixed model. Participants have a baseline measure of the dependent variable, they are then randomised to either placebo ...
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Reference materials for RCT study design where only placebo patients switch to treatment after 10 weeks

I am looking at a study design where the study randomly assigns patients to two groups, 1) Treatment arm or 2) Placebo. After 10 weeks, patients in the Placebo group switch to receiving treatment ...
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Are cross over clinical trials only suitable for drug treatments?

I wonder please if cross over trials are only applicable to drug treatments ? or maybe also to vaccines ? I can't imagine they are appropriate for surgical interventions or for devices, laser or ...
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How to calculate Residuals’s Sum Sq of 3*3 Crossover design analysis

The following program is 3*3 Crossover design analysis in R. I'd like to know how to calculate Residuals's Sum Sq "8.5089". But trying it, it was “7.29”. The image is the table in Excel, and ...
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R: Post-hoc test on lmer. emmeans and multcomp packages

I'm working on a dataset of 2x2 crossover study. I have 10 subjects, each of them underwent both A and B treatment but in a different sequence. (This is a balanced study.) I want to see how A and B ...
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Statistical Analysis of fixed sequence crossover design-placebo followed by medicine

I am planning a fixed-sequence 2-treatment (placebo followed by drug) crossover study. There is a Placebo run-in period of 15 days. Placebo is the control and has no effect on BP. The aim is to ...
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What data analysis would be best to use for my Masters Dissertation?

I will be conducting an intervention where I will be comparing the effects of Kinesiology Tape and Placebo tape on CECS in motorcycle racers. A reading will be taken pre tape application of both ...
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Pooling Different Crossover Data within A Study

I am trying to analyze a double-blind study that has 3 separate crossovers: Dose X mg Dose Y mg Dose Z mg In each cohort, subjects are randomized to either 'Treatment-Placebo' or 'Placebo-Treatment'....
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Cross over design 2x2 with one baseline

I have an experiment that consist in two stages and 24 subjects between three groups. On the first stage, subjects were managed for them to answer in a certain way given the group (growth curve ...
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Equivalence of proc mixed SAS and R lme/lmer

I am looking at a 2x2 crossover study with period-specific baseline measurements and the according post-treatment outcome values Intervention (A or B) Sequence (AB or BA) Period (visit day1 and visit ...
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How to measure carryover effect in a crossover design 3x3?

I'm trying to analyse a potential carryover effect from a study with a crossover design 3x3, three treatments and three periods. My data has a latin square design with the treatment sequences CBA, ...
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Is this a crossover design?

I am working with collaborators who are conducting an education research study to see if there is a difference in learning outcomes between two learning experiences, one with a technology tool (let’s ...
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Analysis crossover clinical trial

I have data from a six-sequence 3-drug 3-phase crossover trial that had a 7-day baseline period pre-study (used to generate mean baseline value). My outcome is a non-parametric continuous variable ...
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Marginal effects in an AB/BA cross-over study

I am currently working on an AB/BA cross-over study. There I have a treatment $T$, a time-varying covariate $X$ and a dummy variables $Z$. I wish to study the interaction between $X$ and $T, Z$. I ...
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Coding of cross-over study's effects in a meta-analysis

One of the studies to be included in my meta-analysis has a cross-over design: between T1 and T2, a first group does the treatment condition while a second group does the control condition; and vice-...
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Pre-post treatment comparison crossover study 2 treatments 2 baselines

I would like to analyse data with a crossover design. Each subject was assigned to a sequence (AB or BA), i.e. 2 periods. Each period consisted of one measurement before treatment (baseline or pre-...
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Is this a valid experimental design?

An experiment to test 2 new treatments was performed in the following setup: Animals were divided into 2 groups: young (A) and old (B). Animals were present for 3 periods. Each group consisted of 81 ...
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Mathematical notation / formula of a mixed effect model

I am unsure how to define the mathematical notation of a mixed model of R. I built the model in this way: ...
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What is the difference between cross-over and repeated-measures designs?

I know that a cross-over experiment (of any number of treatments/levels) necessarily has a repeated-measures design, but that not all repeated-measures designs are cross-overs. However, I wasn't able ...
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How should I specify random effects in a crossover study with lots of repeated measures (continuous time component)?

I don't see any previous questions (with answers) about this exact thing. n=20 patients. Each took placebo then did a task for up to 60 minutes. Response (continuous variable) was measured every 2 ...
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How to analyze combined data from studies with overlap in subjects?

I have data from multiple placebo-controlled cross-over trials (each with $n \simeq 20$) with unique phenotypes measured during the placebo phase. I'd like to combine the data from these measurements ...
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How to handle crossed and nested terms in a crossover design

Here comes my case: I conducted an experiment with the following design: 30 participants, each with a unique id, were screened and classified according to a trait. Then, all participants were tested ...
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How to analyse this semi-cross over study design?

I have this semi-cross over study design. It can be depicted as two different groups - control and treatment. Patients are initially randomized into either control or treatment group. The control ...
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Regression for cross-over trial with small sample size

I am in a bit of a pickle with some data that I have obtained in a collaboration. This is a crossover trial in which 8 elite cyclists were assigned to two experimental conditions at different ...
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Analysis of a cluster crossover design

I am analyzing data from a cluster randomized cross over trial. There are 9 clusters and 3 periods in the data. The clusters are dental clinics and in each period different patients are sampled. I ...
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Correct use of T-Test?

I'm new to Cross Validated and have read some posts but I'd like to ask if I have set up this study and chosen the correct significance test. A quick rundown: Four week study Same 11 Students ...
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analytical methods for crossover study that has an addition control group

I have a crossover study where patients perform a cognitive task (with two conditions) when their brain stimulation is switched on and then off. Using a mixed effects regression, I would ensure that ...
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How does one carry out the Wilcoxon-Gehan test for paired survival data?

In a 2-way crossover scenario, where subjects are randomized in a 1:1 ratio to either a AB or BA sequence, a time-to-response variable was measured after the dosing of treatment A or treatment B. ...
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How to analyze this unusal longitudinal design?

I have data coming from an unusual design. 10 subjects were drawn to receive an experimental eye drop for reducing intraoccular pressure. One eye was chosen by random and the drops were applied. The ...
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Study the effect of 2 drugs on a symptom caused by 2 diseases

A symptom (for e.g. Headache) can be caused by 2 different diseases (X and Y). Drug “A” acts on both diseases (X and Y). Drug B acts on only second (Y) disease. Disease “X” patients will be treated ...
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How to study the effect of 2 drugs (used singly and in combination) compared to a placebo on a disease

I want to study the effect of 2 drugs (used singly and in combination) compared to a placebo on a disease. What is the best statistical method? Kindly provide full details.
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Mixed model for multiple measurements in a crossover study (SAS)

I am currently trying to analyse data from a crossover study. In brief, the study is of a crossover design, where each participant takes part in 2 separate sessions, where they play a game. This game ...
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McNemar test comparing two proportions in a crossover trial

In a crossover trial involving 50 patients, two dialysis treatment schedules were compared.Ten patients complained of vomiting on both schedules, 30 on neither, nine on treatment A only and one on ...
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Most appropriate statistical analysis for a 3 treatment, 3 period crossover design

I have a study looking at a particular blood measure after performing 3 activities (sitting (control), walking (intervention 1) and cycling (intervention 2). There will be a minimum wash out period ...
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ANCOVA for 2X2 crossover with baseline measurements - validity of assumptions

I'm trying to learn how to do ANCOVA for a 2x2 crossover study with baseline measurements. I have followed the analysis performed at Mehrotra 2014 "A recommended analysis for 2 x 2 crossover trials ...
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four period crossover design in lmer or lme4

Our experimental setting is a four-period crossover design: the table below indicates typical types of experimental data. ...
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