Questions tagged [case-control-study]

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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62 views

Use of words “control” and “test”

There are 2 groups of people, group A and group B. The groups were NOT assigned randomly and are not the same size. It is true that group B has a higher rate of success than group A, but this was ...
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1answer
926 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
123 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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41 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
381 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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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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721 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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188 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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2k views

How to make the rare events corrections described in King and Zeng (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
687 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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1answer
32 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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67 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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198 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 ...
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1answer
89 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 ...
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1answer
110 views

Case-control study with data collected in batches

I have (matched) case-control data. The data is collected in batches in such a way that the batch determines some quality of the data (there is a 'batch' effect). Also, the cases and controls were ...
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1answer
4k 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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161 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
10k 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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How to analyse data collected in different ways

Let's say I collect some quantitative case-control data. First thing that pops into my mind is using a t-test to see if these two groups differ. Let's say some more data is collected, but it's just ...
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2k 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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1k 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 whether or not the difference is different ...
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47k 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 $1....
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1answer
246 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 dif-...
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1answer
116 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
1k 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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94 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 ...
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1answer
109 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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867 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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181 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 ...
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1answer
385 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 ...
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6k 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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669 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 ...
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1answer
78 views

Measuring tariff evasion before and after tariff cut

I have data on tariff rates and a proxy for tariff evasion (that is common in the literature). The data spans a couple of years before the country I'm studying implements a tariff reform and lowers ...
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1answer
391 views

Imputing/instrumenting for missing variables in a case-control study

I'm combining two surveys in a case-control design. Survey B is drawn from the "case" population, and includes all the variables I need for analysis, plus some extras. Survey A samples a general "...
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213 views

Probabilities in case-controlled studies

I have a nested-case control study that I have been using for analysis. At the end of my work I have deduced a set of variables that I use later to to classify new cases. One example of a simple ...
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614 views

Review of case control matching algorithms?

Can you suggest a good review of case control matching algorithms? Algorithms that can be used to set up the matched pairs of one case and one control, or matched blocks of a case and multiple ...
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6k views

What does “case-control” and “cross-sectional” mean in the context of logistic modeling?

While studying logistic modeling, I read the following statement The fact that only odds ratios, not individual risks, can be estimated from logistic modeling in case-control or cross-sectional ...

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