Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

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.

0
votes
1answer
24 views

Balanced randomization within clusters

I was hoping someone could point me in the right direction on a randomization method. We want to randomize teachers to receive an educational intervention. The catch is that we have a number of ...
0
votes
0answers
24 views

How to know whether a random effect or a cluster effect is necessary for a mixed effect logistic regression?

I have 8 variables in my model out of which I have a group which is definitely not a fixed effect. I tried checking the random effect on the basis of the log-likehood test and it seems significant. I ...
1
vote
0answers
23 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 ...
0
votes
0answers
67 views

Confidence intervals for survey-weighted Poisson regression in R where counts are totals of the survey weights

Forgive me if this is a very basic question. I am using a large database of healthcare encounters that uses a stratified sampling approach. Each row in the database is a sampled encounter, and has a ...
0
votes
0answers
42 views

Calculating Sample Size for Cluster Randomized Trials with Person-level or Cluster-Level Outcomes

I have been looking for a formula to calculate the estimated sample size for a two-level cluster-randomized controlled trial with cluster-level outcome data. To my reading, several authors do not make ...
0
votes
1answer
24 views

Single DV with repeated/clustered measurements of IV

I have an analytical dilemma wherein I have a single DV with multiple categorical and continuous IVs (one of which is a continuous IV that has multiple measurements across time). I'm not sure the best ...
2
votes
0answers
51 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) ...
1
vote
0answers
48 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 ...
0
votes
0answers
23 views

Sufficient sampling size for logistical regression observational data

As a part of my master thesis, I'm conducting an observational study of journalists' background and the effect of this on the approach to a certain case study. I have a fixed number of observations/...
0
votes
0answers
92 views

R Survey Package and One Stage Cluster Sample

I have a data set with 450 clusters of unequal size. I wish to select a probability proportionate sample of clusters with replacement (PPSWR) and measure an attribute within each of the sampled ...
1
vote
0answers
139 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 ...
1
vote
0answers
50 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 ...
2
votes
0answers
76 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: ...
2
votes
1answer
802 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 ...
1
vote
0answers
277 views

GEE with independent working correlation matrix vs GLM on twin pairs yield different confidence intervals

I have a data set with about 2000 twin pairs and want to apply a logistic regression to it while taking account of the correlated observations (twin pairs = clusters). I use the GEE procedure in SPSS. ...
1
vote
2answers
83 views

GEE all clusters of size 1 have same outcome

I have a large population of patients and hospitalization (>1 million) information. I'm trying to look at the relationships between various predictors and hospital re-admissions within 30 days. The ...
1
vote
0answers
23 views

How can I account for clusters at different observational levels than the independent variable?

My independent variable, $Y_i$, has observations at the group-year level. However, I know $Y_i$ is not independent for all $i$ because the same individuals will be in a group for several years in a ...
1
vote
1answer
544 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 ...
0
votes
1answer
40 views

Random sampling with different stages

I'd appreciate some help solving this sampling issue: I have select a random sample of people for a survey in a certain country. The country is divided in 6 regions. In total, there are 981 ...
1
vote
0answers
45 views

Sample size calculation of a national study

We want to conduct a national study to estimate a prevalence of certain disease. we still confused about the sample size calculation and the criteria of selecting a representative sample. First: is ...
2
votes
2answers
210 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
votes
1answer
691 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 ...
3
votes
1answer
175 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 ...
1
vote
2answers
208 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 ...
2
votes
0answers
550 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 ...
2
votes
0answers
97 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 ...
1
vote
1answer
49 views

Identifying a single cluster from multiple clusters per customer

Although I have worked out several possible approaches, am curious if anyone has a better best practice to recommend? I have a large set of customer events (online behavior: 1 mil. records, 20 ...
2
votes
0answers
151 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 ...
1
vote
0answers
28 views

How do I determine the necessary sample size for this data?

I want to estimate enlistment of African American soldiers in the Union Army (during the American Civil War) by county in order to regress this variable on county-level post-war outcomes. I ultimately ...
1
vote
0answers
81 views

How to calculate a sample size in the case of a stratified 3 degrees sample design ?

I am trying to calculate the sample size (and the repartition between PSUs and SSUs) needed to obtain an estimation of a proportion (that I assume to de around 50%) with a 0.05 standard error in the ...
4
votes
1answer
230 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 ...
1
vote
0answers
146 views

Expectation Value of Standard Deviation from “k” Closest Samples

The question that I'm am trying to answer is how to determine the expectation value of the standard deviation of 'k' closest samples to value 'A'. The standard deviation and mean of the underlying ...
3
votes
0answers
40 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 ...
1
vote
0answers
69 views

Is controlling for cluster good enough in an analysis with a clustered sample?

I'm trying to understand how sampling design affects analyses and I'm a little confused about how to adjust for clustering. From what I've read, when you have a clustered sample you are supposed to ...
1
vote
0answers
235 views

one sample t test for clustered data in R

How shall I do one sample t test for clustered data? For instance, I have N = 100 number of observations, which are obtained from 5 different regions. I'd like to test whether the outcome y is ...
3
votes
0answers
394 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 $N$ ...
0
votes
1answer
538 views

Clustered data in logistic regression analysis

I am doing a logistic regression analysis, for an election setting. My dependent variable is voting for the incumbent candidate (Yes/No) and my independent variable is perceived economy (data from a ...
-1
votes
1answer
193 views

Clustering structured data

Does clustering make sense at structured data? I have a sales data set from a retail company. The data is structured into Product Lines, Product Groups and Colors and Articles. I wanted to make a ...
2
votes
0answers
171 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 (...
0
votes
1answer
1k views

Sampling weight for calculating prevalence in two-stage cluster sampling

In study there was used two stage cluster sampling technique. First stage, 16 clusters is selected from 100 clusters using PPS. Clusters are heterogeneous in size. In second stage, 12 households are ...
3
votes
3answers
891 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....
1
vote
0answers
227 views

Cluster Sampling involving Design Effect

A survey of residents is performed using cluster sampling. The design effect is 3.00. From the survey, the estimated proportion of people who are happy with their insurance company is 0.42 with a ...
0
votes
0answers
518 views

How to estimate survey data at cluster level in a stratified clustering survey design?

While estimating from the survey data involving stratification & clustering survey design and using survey package of r, is it possible to estimate at the cluster level? For eg; for following ...
1
vote
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-...
5
votes
2answers
6k 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 ...
2
votes
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 ...
0
votes
0answers
273 views

How to detect clustering or related anomalies in cross-section data

I have a cross-section of 100,000 individuals and information on their age. I suspect that there may be clustering by age or that the sample exhibits behavior that there would be two groups, the old ...
0
votes
0answers
36 views

Ideas for sampling design

I have a data base of schools per district and the number of teachers per school. I want to select a sample where between 1 an 10 schools are selected in each district. Once a school is selected, the ...
1
vote
1answer
105 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 ...
0
votes
1answer
87 views

What does intracluster correlation mean?

I am studying the topic of cluster sampling. I have learnt that intracluster correlation ($\rho$) measures the correlation over all clusters between distinct elements in the same cluster. I do not ...