An observational study in which two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute.

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Survival probability for a case-control study

I have a case-control study in which 21 patients with a certain clinical outcome and 20 patients without that clinical outcome were (retrospectively) selected from a larger group of patients who were ...
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15 views

Matching and study design

I am currently designing a retrospective case-control study and am having some difficulty coming up with an adequate matching solution. The study assesses a specific surgical procedure and the only ...
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1answer
27 views

Analysing a genotypic 2X2 table instead of a 3X2 table

This could be a simple question to seasoned statistical genetics folks. I have delved into this doing an analysis for a friend on the sideline of a bioinformatics task I was helping her with. An ...
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2answers
25 views

Test Control. A longitudinal study

I have two samples of the same size, one being the 'treated' group, and the other used as a 'control' group. Each group have a different univariate variable (stress level), repeatedly observed over ...
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1answer
27 views

Treatment and Control group, the sample size

I am doing the evaluation for a program with 200 members (they enrolled in the program at different times in the past year and the program doesn't end). Only 78 completed the pre test survey. Now I ...
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17 views

Estimating counts (case number) by logistic regression model

The work we are actually facing is estimating case number of a particular health condition. The classification of the case status (Yes or Not) requires at least one positive lab test result and one ...
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1answer
72 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 ...
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12 views

Do I cluster SEs when the cluster variable is related to the DV?

As part of a case-control study, I am using a logistic regression model to predict whether or not youth were in high school or a detention facility. Data were acquired at one time point, in a select ...
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23 views

Confidence interval odds-ratio matched case control

Consider having a list of pairs of binary data denoting observations from a matched case control study. The list may be used to set up a contingency table and an odds-ratio can be calculated by ...
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12 views

Power of a case control test as a function of P(X=1) & P(Y=1)

For our course in statistics we had to build a simulation which would give insight in the power of a case-control study vs that of a cohort study, both trying to discover an association between 2 ...
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25 views

What analysis is appropriate for this matched case/control?

My boss and I are debating which analysis is appropriate for this situation. To make this simple let's say I want to compare age and gender between cases and controls. The matching is done 1:5 ...
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28 views

Simulating Case-Control-Covariate Data

I generate data with a covariate $Y_1$ and disease liability $Y_2$ using the following model: $\begin{pmatrix}Y_1\\Y_2\end{pmatrix} \sim \mathcal{N}\left( ...
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55 views

Interpretation of plot.gam for binomial response in R

I want to evaluate the dose-response for a continuous variable on the risk of a disease using a GAM-model in the mgcv package. The data I have is of case-control design. I need help with interpreting ...
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34 views

Nonlinear form of ANCOVA?

I would like to compare a control group against a test group using something like ANCOVA. However, the covariates are not simple, as some items may have already been increasing with time, others ...
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68 views

why can't I use random sampling in logistic regression when classes are unbalanced?

I don't understand why in a logistic regression model if we have lots of y=0 and few y=1 in the population and I use classical logistic regression (so the classical maximum likelihood estimator), then ...
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1answer
147 views

intercept bias in logistic case-control regression: which is the reason?

I don't understand the reason why if I use case-control sampling in a logistic regression then the intercept is biased. The book Agresti 2007 (An introduction to categorical data analysis) says: ...
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1answer
46 views

reference case-control sampling

I have to use a case-control sampling design to apply logistic regression. I'm looking for a reference that explains which are the advantages and disadvantages of using a high case-control ratio ...
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28 views

Join data sets from retrospective studies

I'm doing the analysis for a study where we need to assess the effect of surgery A (hand surgery) on condition B (trigger digit), adjusting for confounders via logistic regression. The problem is ...
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1answer
40 views

What is the definition of “population” in Case-Control Study?

Why in case-control studies, cases and non-case are taken from "Two-different Population?" Why don't they come from a single population?
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39 views

Inference possibilities for matched case-control study

We have contracted out collection of survey questions for the group of our customers. These customers even when sampling all of these represent less than 1% our our customer base. We would like to ...
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11 views

Dealing with gender bias in Clinical Field Study - non parametric data

I have 105 patients to compare to 191 non-patients, across numerous non-parametric variables. However, my key confound is gender: 60% male in the patient group and 35% male in the non-patient ...
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20 views

Age-at-event-stratified analysis for different case-control designs

My question is whether you can perform age-at-event-stratified analyses for: cumulative case-control studies (controls sampled at end-of-study) nested case-control studies (incidence density sampled ...
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72 views

Bootstrap confidence interval for case control data in R

I have a matched case-control data material and am estimating a risk-measure parameter with a certain estimator. I want to use bootstrap methodology to estimate confidence intervals for the parameter ...
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20 views

Clustered samples in case control studies

In health systems research, in which data is usually gathered from practices or clinics, why are case control studies often designed without correction for design effect?
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1answer
160 views

Case-crossover method with conditional logistic regression for poisson model generated data

I would like to run a semi-symmetric bi-directional case-crossover method on some generated data using conditional logistic regression. I generated data from Poisson distribution Poiss(lambda) with ...
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30 views

Selecting from a bigger control group for 1:1 ratio

What I have is a treatment group consisting of 90 individuals. I have a pool of individuals eligible for my control group, which I want to be matched by age and gender in a 1:1 ratio. Is there any ...
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37 views

How to handle data with double the number of cases than controls?

I have genetic SNP data with 50 controls and 120 cases. I am said that comparing few controls with more number of cases will cause spurious associations. The analysis that I want to do is just a ...
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302 views

How to make the rare events corrections described in King and Zheng (2001)?

I have a dataset with a binary (survival) response variable and 3 explanatory variables (A = 3 levels, B = 3 levels, ...
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1answer
176 views

In a matched case-control study, what do I use for hypothesis testing in the descriptive statistics or the “univariate” associations?

I am doing a case-control study with 80 disease cases matched 1:3 to non-diseased controls and examining whether they had a binary exposure prior to developing the disease. I am using multivariable ...
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51 views

Retrospective Case Study

I am carrying out some research and am a novice to statistics, having done a 2 week module primarily focusing on parametric data and experimental design. However, for my research I am doing a ...
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1answer
23 views

sampling question

I have a question about inclusion criteria to obtain a representative sample of people with "sustained" or uncontrolled high BP. A colleague proposed that I look at health history data retrospectively ...
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22 views

RTM and study design issue

I was asked to estimate "regression to the mean" (RTM) error for the purpose of measuring program efficacy for reducing spending among the highest spending individuals. Given the constraints of the ...
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54 views

Optimal way to match cases and controls w/ multiple per strata

I need to do a matched analysis. However, I cannot find good reference for the best way of matching when each stratum may contain multiple cases and controls. As an extreme example, say we want to ...
3
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1answer
66 views

Proper Sampling - can I collect a two-group sample this way without issues? [duplicate]

I need to collect a two group sample for a comparison analysis (perhaps using logistic regression). The population that I need to extract a sample from is all firms from country A with activities in ...
3
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1answer
416 views

Case-control study and Logistic regression

Suppose we have case-control data, where cases have some disease ($Y$) and controls don't and we are interested in the association of some other variable(s) ($X$). I know that in this scenario we ...
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99 views

Power calculation for case-control study

My study is assessing whether there is a correlation between two medical conditions (endometriosis) and bleeding disorders. The case participants have endometriosis and the controls do not. In both ...
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1answer
1k views

Does down-sampling change logistic regression coefficients?

If I have a dataset with a very rare positive class, and I down-sample the negative class, then perform a logistic regression, do I need to adjust the regression coefficients to reflect the fact that ...
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1answer
600 views

Estimating logistic regression coefficients in a case-control design when the outcome variable is not case/control status

Consider sampling data from a population of size $N$ in the following way: For $k=1, ..., N$ Observe individual $k$'s "disease" status If they have the disease, include them in the sample with ...
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254 views

What is the difference between a frequentist approach with meta-analysis and a Bayesian approach?

Say I am performing an analysis looking at a particular health measure. I am interested in the difference in that measure between patients and controls and wether or not the difference is different ...
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3answers
2k views

How to interpret odds ratio?

Suppose we have a baseline exposure group and 2 other exposure groups for a case control study. Suppose the odds ratio for the first exposure is $1.5$ and the odds ratio for the second exposure is ...
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1answer
98 views

Is this a case control study or a retrospective cohort study?

From the echocardiography database at a tertiary care center, 1,625 subjects (mean age, 44 6 14 years; 47% men) with normal echocardiographic findings between 2000 and 2009 were identified. Gender ...
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1answer
66 views

Case Control Study

Suppose we have identified $20$ cases from a population of $1000$ people. $15$ of these cases are male. We want to use one-to-one matching to choose the control group. We would match on gender. So ...
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1answer
171 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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68 views

Are case-control studies one example of an extreme group design?

I need to present some research to a field that commonly uses case-control studies (comparing those with a disease versus those without) and it just occured to me that an extreme group design (which I ...
3
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1answer
80 views

Sources for sampling in case-control studies

In my previous job as a statistics teacher, I was involved in studies mostly as an advisor on a general level. Not that much hands-on experience from doing the actual sampling or data cleaning, ...
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450 views

Determining whether two samples come from the same population and which hypothesis test is appropriate

I have a study conducted by a team of doctors: two groups of people were treated for stress urinary incontinence in two ways: TVT and abbrevo. Each group consisted of 23 people. The hypothesis is as ...
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101 views

Can I validly expand the odds ratio analogously to the relationship between relative risk & the incidence rate ratio?

I am involved in a nested Case-Control study that involves cohorts of cases and controls entering a program, with the outcome of failure by six months. Cases and controls are individually matched on ...
5
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1answer
243 views

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 ...
8
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2answers
2k views

Optimal case/control ratio in a case-control study

What is the optimal case/control ratio in a case-control study? Why do most textbooks or monographs suggest that it is more than 1? Can it be less than 1 (what are the drawbacks?)? Thank you.
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489 views

Using controls as basis for quantile/tertile categorization

I have a number of continuous but really skewed variables in the statistical analyses I am currently performing. Even though I am strongly in favour of keeping them just as they are and relaxing ...