A study design in epidemiology: a subset of a cohort study are more intensely measured at baseline, while the whole cohort is followed for outcomes. Primary analysis compares baseline experience of “controls” to baseline/follow-up experience of cases.

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How do I perform a statistical analysis on an intervention based study?

I am trying to get my head around the best way to analyse a study. The study comprises of persons that get given a number of up to 10 different interventions, whereby hospital admission frequency is ...
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What test to use when analysing methylation differences with very small sample size?

I have not been capable of figuring out which test to use for my data, so I hope you can guide me in the right direction. I have array DNA methylation data for 5 families. From each family I have ...
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Epidemiology cohort studies question

If we are conducting a cohort study of factors associated with recurrent myocardial infarctions (MI) following the first one, should our study population at baseline include subjects who had ...
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58 views

Cohort analysis for media site

I'm trying to find a reasonable way to measure retention of a site (news site). I'm trying to do cohort analysis: I've grouped all visits by year/week, and measured the percent of users that kept ...
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91 views

Predicting new data using a Case-cohort Proportional Hazards Model

I am fitting a Case-Cohort Proportional Harzards (CCH) model using the Survival (version 2.37-4) package in R 2.15.3. Normally with a Cox Proportional Harzards (coxPH) model, I can use the survfit ...
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What to use: Nested Case-Control or Case-Cohort?

I am following a cohort of patients over time from which I am planning to sub-sample a sub-group of patients to pilot a new intervention. The plan is to compare the effectiveness of the new ...
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127 views

Dividing controls between two groups of cases

I have a set of data that contains cases and controls. I would like to divide the cases by a particular phenotype before running my tests, to see how these groups differ (but not necessarily to ...
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67 views

R CCH CI Univariable Analysis

Using the survival package in R I am trying to calculate 95% confidence interval (CI) of the proportional hazards model coefficient. Normally this is pretty simple to do with the survival package. ...
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Follow-up updates in case-cohort designs

In a case cohort, you randomly sub-sample some feasible number of the cohort (say 20%) and then afterwards add all of the cases that were not part of the sub-sampling. So while a case-cohort is easy ...