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.

Filter by
Sorted by
Tagged with
0
votes
0answers
18 views

Clustered pre-post analysis dichotomous variables in SPSS

I’m not entirely sure how to analyze data we have from the following study: We trained three teams of health care professionals of three different palliative care wards We would like to analyze the ...
1
vote
0answers
10 views

Statistical analysis of clustered data- but clusters in one comparison group only

I'm curious if it's still valid to use analysis techniques for clustered data when only one of the two comparison groups consists of multiple clusters. For example, the control group consists of 10 ...
0
votes
0answers
26 views

How do I incorporate clustering in a matched case-control analysis?

I am trying to analyze a 3:1 matched case control study (matched on age and date of medical encounter) but realized that there may be household clusters represented among cases and controls. Cases ...
0
votes
0answers
21 views

How can i calculate density of every centroid in python

i have kmeans clustered data, and cluster centroids of the kmeans. I want to calculate density of each cluster centroid and remove the cluster of the highest cluster centroid density. I did my ...
0
votes
0answers
15 views

AutoEncoder and Unsupervised Clustering

I am working on a dataset of ~300 samples with ~5000 data-points each - ranged between 0 and 100. I am interested in: Group samples for similarity; Find the differences between groups; Would make ...
3
votes
2answers
78 views

Determine sample size for each cluster

Suppose I have a large population and I want to test if installing a new special light bulb can reduce energy consumption. Since I have a large population, I'll have people that usually consume high ...
1
vote
1answer
71 views

If fixed effects and robust standard errors both necessary, do they have to be at the same level, and why?

I am working on an empirical paper using repeated cross-sectional data, and a reviewer has asked that we cluster our standard errors at the same level as our geographic fixed effects. Given the ...
0
votes
0answers
22 views

Coding systematic designs with multiple random starts

I am trying to set up a survey design using the survey package. We sampled 0.5m transects systematically from a 100m reach and used 3 random start locations thinking it would provide a better ...
1
vote
1answer
176 views

Single Observation with Some Groups. Multilevel model or other analysis?

I am having trouble determining which method to use to analyze my data. Here is the info: -575 observations nested within 292 groups -some groups only have one observation, the max number is 23 in a ...
7
votes
5answers
278 views

Are the differences between sampling clusters and sampling strata, conceptual, methodological, neither or both?

I am fuzzy on the distinctions between sampling strata and sampling clusters. Both seem to aim at designs aiming at creating useful estimates of between/within group (strata, cluster) variation, and ...
1
vote
1answer
13 views

Stratified Sampling - Confim usage and sample size

I want to conduct a survey on a population of college students to run models on. My hope is that it will accurately represent the population. I am concerned about the sample not giving a close ...
2
votes
2answers
46 views

If you match within clusters,do you still need to use a multilevel model?

I am reviewing an article. I can't share details because the article has not been published but, briefly, the authors studied people with and without a condition and looked at long term sequealae of ...
0
votes
1answer
42 views

Algorithm to get representative sample

For a dataset I wanted to pick-out some most representative points from it. Lets say the first point could be centroid, next could be the one farthest from it in the data-set(To get variance in data) &...
0
votes
0answers
10 views

How can I apply a design effect of 2 on my fisher's test and/or regression?

I'm trying to use R or statistical analysis on a multicluster sampling and specifically to inform it that I have a design effect of 2. I've familiarised myself with the survey package and tried to ...
0
votes
0answers
26 views

performing a multilevel logistic regression: data naturally clustered but small clusters, singletons and limited number of 2nd level clusters: help?

I am looking to perform a binomial regression calculating the reselection chances of parliamentarians in the European Parliament based on their activity levels. DV= reselection: 0/1. My data is ...
1
vote
0answers
27 views

Derive an expression to estimate the total number of clusters N, with unequal cluster sample sizes m

The task in the question below is to determine the number of clusters required for a "cluster randomised crossover" design conducted over two 6-month periods, with m = subjects per cluster per period, ...
0
votes
0answers
15 views

CLUSTER SAMPLING PROOF

i have one questions that referred to book "On Efficiency of Cluster Sampling" (Daroga Singh, 1956) and my problem is i don't have that book, 9.14 The following sampling schemes for estimating the ...
3
votes
1answer
47 views

How can I model clustered data in a regression?

I have a dataset of $N=3000$ biopsies from humans, each of which have an outcome I am trying to examine using covariates of the patient who provided the biopsy. Some biopsies from the same patient ...
5
votes
1answer
93 views

What regression model to use for both repeated measurements and cluster data (and how to do it in R)?

My research question involves looking at association between the characteristics of neighborhoods (% male, % female, income, % young people, % old people) and the participation rate in a programme (% -...
2
votes
1answer
49 views

Why is the equation for Intra-class correlation aligned with design effect of cluster sampling?

The design effect definition (link) is: $$ DEFF = 1+ (m-1)*ICC $$ It is also the relationship between the variance of estimating the mean with the cluster sampling divided by the variance if the ...
4
votes
3answers
736 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 $$ \bar y_{j[i]} = \alpha + \beta x_i + \varepsilon_i $$...
2
votes
1answer
171 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 &&...
1
vote
1answer
80 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 ...
0
votes
1answer
28 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
65 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
1answer
56 views

Analyse continuous variable between two groups/arms: cluster randomized study

I'm analysing the data for a cluster randomized study. There are 66 clusters randomly divided into two study arms: control and intervention, 33 clusters each. In total there are 2098 patients. The ...
1
vote
0answers
35 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
160 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
63 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
26 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
83 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
199 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
64 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/...
1
vote
0answers
273 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
83 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
110 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
2k 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
357 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
132 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
33 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 ...
3
votes
1answer
1k 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
47 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
49 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
413 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
1k 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
215 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
289 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
634 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 ...
5
votes
1answer
264 views

Does clustering lead to overdispersion?

TL;DR Clustering is often cited as a source of overdispersion in count data. However, I seem to arrive at the conclusion that clustering actually reduces the dispersion. Could someone confirm this ...
2
votes
0answers
104 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 ...