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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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Modeling Condition Specific Associations

I am trying to model a crossover repeated measures design in which individuals complete both the active and control conditions. These individuals also complete cognitive testing before and after both ...
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reproduce an analysis of a simple crossover trial using GEE from a paper

I am trying to reproduce the results in Table 6 from this paper entitled "The analysis of binary and categorical data from crossover trials". https://journals.sagepub.com/doi/epdf/10.1177/...
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Williams design for cross-over study

i need a little help. I'm reviewing a cross-over study with n = 25 subjects and t = 5 treatments. R library crossdess and the function williams.BIB() was used to combine a balanced incomplete block ...
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Mixed effect model for repeated measurements in crossover study using R

I am trying to analyze data from a crossover study. The study has two phases and subjects are randomized to received either treatment A or Treatment B first, and then switch to the alternative ...
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A complex crossover study: addressing unbalance and time effects

I'm analyzing a crossover study, where subjects are measured at two time points during each treatment phase (Placebo or Treatment). Additionally, baseline measurements were taken before the experiment ...
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Exploratory study with multiple testing

I have conducted a study with 20 participants. During the study I measured 9 different plasma hormones at 5 different times before and after an intervention. As an exploratory study I would like to ...
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Evaluating a cross over design with a very strong carry-over effect

I'm wondering how to properly evaluate a trial which was performed using a cross-over design evaluating two instruction techniques. Group A is instructed by technique 1, Group B by technique 2, both ...
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Interpret results of a mixed effects model analyzing a 2x2 cross-over study?

I have conducted a randomized 2x2 cross-over trial of 8 participants measuring the effect of a specific diet (intervention) vs normal diet (control) on the number of sleep hours. The study design ...
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Intention to treat principle in randomized crossover trials

Is it possible to use intention-to-treat principle in randomized studies with crossover design? Was it ever used in such studies?
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Linear mixed model for crossover trial with repeated measure levels in SPSS

I have data from a study where participants completed 3 interventions in a randomized order (1 week washout period), and where in every intervention, outcome measures were taken every 15 minutes over ...
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fixed-sequence, crossover clinical trial in food allergy

I want to conduct a fixed-sequence, crossover clinical trial to compare the effect of stopping allergic food at one time period with that of another time period when they eat the allergic food. When ...
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Paired vs unpaired samples t-test in crossover study

I have to analyse a 2x2 AB/BA crossover study, in which every participant was administered drug A and then no drug at all, or vice versa. There were two study visits and in each visit the peak glucose ...
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Can I conduct an exploratory cross-over study on data originally collected in a clinical trial?

I need your opinion about this study. Originally it is a clinical trial comparing two treatment regimens (of IVF) on the chance of fertility. One (Treatment A) consists of ovarian stimulation during ...
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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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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 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 ...
Daisy Chang's user avatar
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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 ...
Carrie's user avatar
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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 ...
user114582's user avatar
1 vote
1 answer
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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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4 votes
1 answer
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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 ...
z8080's user avatar
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3 votes
2 answers
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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 ...
Frank Brube's user avatar
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732 views

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 ...
rcirer's user avatar
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2 answers
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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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1 vote
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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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3 votes
1 answer
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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 ...
Jonathan Marin's user avatar
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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 ...
George Youssef's user avatar