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Questions tagged [cluster-sample]

Cluster sampling is a sampling design in which the observation units have to be grouped together for logistical reasons (e.g., students clustered in schools or households clustered in a geographic area). Typically, cluster samples are multistage samples, so geographic areas are selected in the first stage and households in the subsequent stage.

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11
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1answer
4k views

Fitting multilevel models to complex survey data in R

I'm looking for advice on how to analyze complex survey data with multilevel models in R. I've used the survey package to weight for unequal probabilities of ...
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2answers
7k views

Simple way to cluster histograms

I'm trying to cluster set of histograms. The histograms represent the frequencies of the distribution for a numbers from 1 to 5. The following figure shows two samples of my data. I have 10,000 ...
6
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2answers
346 views

Agreement in clustered sample data

I have analyzed several data curves from a group of patients (16 curves per patient) with different analysis methods and want to test for the agreement of the methods. So far, I have neglected the ...
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3answers
906 views

Why are samples within a cluster less informative than randomly chosen ones from entire population?

Please give me mathematical explanation if possible. And also in the book Kothari 2004, it says: There is also not as much information in ‘n’ observations within a cluster as there happens to be in ...
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1answer
243 views

Survival analysis for patients that have been subjected to multiple treatments

I have data for patients that were subjected to either one treatment or multiple treatments at various points in time and I need to analyse their survival times after treatments. This of course means ...
4
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1answer
550 views

Power calculation for cluster-level analysis in cluster randomized trials

I would like to solve for $\pi_1$ in equation 7.14 of Hayes and Moulton's Cluster Randomized Trials. I can't for the life of me remember how to do so. Here is a link to the equation. $$ c = 2\;+\;(z_{\...
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3answers
939 views

Standard error clustering under treatment assignment in groups of varying size

Basic setup: Unit of observation is the individual. Treatment (binary) is assigned on city level. Every state contains 4 cities, 2 get randomly chosen for treatment, 2 control. There are only few (e....
3
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1answer
183 views

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 ...
3
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1answer
205 views

Defining PSU in “Sampled with Replacement” Cluster Samples

I am trying to decide on an approach to estimate design effect for a multi stage cluster survey. The clusters were selected with probability proportional to size sampling WITH replacement. The ...
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0answers
41 views

How to analyse paired data lacking pairing information? [duplicate]

A colleague has a dataset from a before and after study looking at a continuous outcome that was measured in individuals before and after an intervention. An unknown but not insubstantial proportion ...
3
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0answers
431 views

Effect of modelling matched data via fixed effects

A simple approach to handling matched or clustered data would be fit a regression model that includes fixed effects corresponding to matched pair or cluster ID. For example, with 1:1 matching on $N$ ...
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1answer
515 views

What is the advantage of clustering (multilevel sample)?

(This is a question about the case study on page 636 of the book Applied Longitudinal Analysis by Fitzmaurice, Laird and Ware) The data consists of 1028 weights of mice fetuses, they are clustered in ...
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3answers
114 views

Regression model with aggregated targets

Similar as in this self-answered question, I want to ask about possible approaches for modelling data with aggregated targets, i.e. things like $$ \bar y_{j[i]} = \alpha + \beta x_i + \varepsilon_i $$...
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2answers
224 views

Robust Variance Estimate with Cox model in Complex Survey Setting

I have a single-stage cluster sample, and I am trying to estimate the hazard ratio of a given exposure after controlling for a confounder. My dataset contains 10 strata, with 20 clusters within each ...
2
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1answer
1k views

clustered-stratified random sampling

i've got questions about clustered-stratified random sampling. let's say I want to do a research in narcotics. the population that I will be working with is a combination of academics, students, and ...
2
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1answer
992 views

Causes for Underdispersion in Poisson Regression

I am working with count data (number of pregnancies per woman), and using glm Poisson (log-link) to model determinants of the former count variable. From simple descriptives I observe that my data ...
2
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1answer
829 views

Does # of observations in each cluster matter for cluster-robust standard errors?

In multiple regression with panel data, when calculating cluster robust standard errors, does it matter if there are only a handful of observations in each cluster? I am looking at if the ...
2
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1answer
469 views

Repeated measures vs. cluster in logistic regression

I have data from an experiment in which participants played a repeated game 50 times. That is, I have 50 data points per participant. I want to run a logistic regression and I have of course to take ...
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0answers
54 views

Why doesn't clustering bias the standard errors in this very simple simulation?

I simulate a very simple model with one regressor and a random intercept: $$y_{ij} = \beta_0 + \beta_1x_{1,ij} + u_j + \epsilon_{ij}$$ I run model <- lm(y ~ x1) ...
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0answers
84 views

How to estimate variance for identical & fraternal twins with a mixed model

I am using the twins data from OpenMx and am curious to estimate the empirical covariance structure for BMI differences in monozygous and dizygous twins: ...
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0answers
578 views

Sample size calculation for Cluster randomized trial

In the following Paper by Clare Rutterford, Andrew Copas and Sandra Eldridge, the following formula is given for sample size calculation: assuming the following properties: • m - number of clusters ...
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0answers
99 views

Which bootstrap for small set of independent data?

I am thinking which bootstrap to choose for studying MIT-BIH arrythmia database (44 patients) in time-domain and Fourier-domain. I need to find a variable which can allow me to determine ...
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0answers
184 views

For boostrapping: stratified or cluster sampling?

I am trying to apply bootstrapping on several regression models to obtain SEs of parameters. My question is about preparing the bootstrapping samples in proper manner. The data I am working on are ...
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0answers
175 views

Power calculation for multiple level clustering / randomization using simulations R

I am trying to calculate power of the following design: -Treatment is randomized over a small number of clusters (1st level clustering=regions) -Within each region we randomly select villages (...
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0answers
2k views

Calculating needed sample size for two stage stratified cluster sample

We want to carry out a survey to assess perceptions of quality and access to medical education of last year students. Based on our research, we have decided that a two stage stratified cluster sample ...
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0answers
96 views

Cluster weights in PROC GLMPOWER

I am doing power analyses in SAS using PROC GLMPOWER to solve for a total sample size (N Total). I have clustered data (Ward method), to account for variability. There are 4 clusters of varying sample ...
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0answers
188 views

When do sample size calculations need to adjust for clustering?

I am aware that sample size calculations for cluster RCTs must adjust for clustered data. I would like to understand better if such adjustment might be necessary for other study designs. For instance, ...
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0answers
883 views

Sample Size Calculation for Cluster Sampling

I'm being asked to calculate a necessary sample size for a cluster sampling protocol. I don't have much experience with cluster sampling, so thought I'd come here. The situation is as follows: 1) ...
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1answer
114 views

Adaptive Sampling Design

In a pdf, the definition of adaptive sampling design is written as : "An adaptive sampling design is one in which the selection of units to include in the sample depends on ...
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3answers
43 views

What does this definition, $\bar{Y}= \frac{\sum^M_{i=1}\sum^{N_i}_{j=1} Y_{ij}}{\sum^{M}_{i=1} N_{i}}$, mean?

I am studying the topic of cluster sampling. Within this topic I have learnt that the mean per element is defined as $$\bar{Y}= \frac{\sum^M_{i=1}\sum^{N_i}_{j=1} Y_{ij}}{\sum^{M}_{i=1} N_{i}}$$ $M$ ...
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1answer
57 views

which statistical sampling technique to employ to have a representative sample

There is kwashiorkor outbreak in my community Abeng (a city in Africa). The community is in sections A to F and it heterogeneous in nature.
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1answer
21 views

SMD meta-analysis including cluster-randomised trials: is it possible? If so, how?

Where we have cluster-adjusted results from trials (summary statistics), under what circumstances can we include them in a standardised mean difference (SMD) meta-analysis and which calculations are ...
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2answers
226 views

Are clusters in cluster sampling made randomly?

Knowing that in cluster sampling the population is divided into clusters and a simple random sample is taken of them and then all the elements of the chosen clusters are sampled, are the clusters in ...
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1answer
469 views

Horvitz-Thompson estimator for two-stage cluster sampling

So I want to apply the Horvitz-Thompson (H-T) estimator to two-stage cluster sampling. The H-T estimator is defined as: $$\sum\frac{Y_i}{\pi_i}$$ where $\pi_i$ is the probability of including the $...
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1answer
309 views

Cluster randomized sampling and subseqent analysis

I am currently designing the sampling strategy for a prevalence survey on elderly in long term care facilities (LTCF) in my service, I used the "Limebook" from WHO as a reference. And I would like to ...
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1answer
22 views

Is it necessary to fit cluster-level covariates for mixed models?

Suppose I have the following two generalized linear mixed models (GLMM): \begin{align*} g(\mathbb{E}[Y_{ij}|X_{ij}]) &= \beta^\intercal_1 X_{ij}^{(1)} + \beta_2^\intercal X_{i}^{(2)} + U_i &&...
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1answer
636 views

Standard Error For Cluster Sampling

A problem I've found and been thinking about for a while but not sure I can articulate properly. Any help appreciated. A survey is being planned with the goal of interviewing $n$ people ...
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1answer
2k views

Case-control Matched Clustering in Generalized Estimation Equation (GEE) (R:geeglm)

Question: I have matched case-control data and I would like to take advantage of that in my GEE analysis. In the standard approach to GEE analysis, we call each subject a cluster and fit subject-...
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1answer
330 views

Calculate sample size to determine freedom of disease with two level clustering

I'm trying to find a calculation that will allow me to calculate both: the number of farms and the number of sheep per farm I would need to sample to determine the absence of a disease for the ...
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1answer
484 views

geeglm not recognizing clusters

I am fitting a geeglm model and it is not recognizing the clustering. my model is ...
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1answer
85 views

Which statistical test to use with repeated measures & clustered observations?

I am doing an experimental study for my research. I have a class with 24 students and six groups, where each group includes 4 students. I want to compare the performance of each group in two cases: ...
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1answer
219 views

Two-stage cluster sampling problem

I'm having difficulty understanding the following problem. It seems like it is a two stage cluster sampling problem, but then the defective red lightbulbs make the question even more difficult. I'd ...
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1answer
262 views

Cluster-randomized trial: mixed model hypothesis testing

I want to estimate the effect of randomly assigned intervention. The outcome is measured at the individual level, but the individuals are assigned to groups which influence eachother a lot, and it is ...
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1answer
843 views

How can I make clusters with highly right skewed data?

My histogram of expected income is as below. As you can see, income is highly right skewed. I want to divide individuals with regard to income - for example into Low, Middle, and High, and then I ...
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1answer
1k views

use spss to analyse a cluster randomized data

I have data from a cluster randomized trial, that is, each subject in the same cluster has received the same treatment. Do chi square test and t-test need some adjustments? More precisely, which ...
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1answer
83 views

longitudinal models for prevalence

I am trying to analyze some prevalence data and estimate the effect on prevalence of some health condition of an intervention that was introduced at some time point. The data concern a number of ...
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0answers
27 views

IPD meta-analysis: need to weight regression and population level estimates?

Using individual patient data (IPD) from various studies, do I need to weight observations in a meta-analysis? Each study used a two-stage cluster sampling design with uniform samples per cluster and ...
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0answers
93 views

Power Calculation in R for CRCT with outcome on individual level

I would welcome any help with computing power calculations for cluster randomised control trial and specifying the code in R for this. I've been trying to use clusterPower package but any R package ...
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0answers
168 views

Clusters in Cluster Analysis and Sampling

In Cluster Analysis, clusters are usually "homogenous within" (that is, units within a cluster are close to each other ) and "heterogeneous within" (or clusters far from each other). In Survey ...
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60 views

Linear mixed effects model for twins

I have a dataset which contains data on MZ twins, DZ twins and unrelated individuals. The predictor and response are binomial variables and the effect size of the predictor may vary depending on the ...