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16 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 ...
0
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0answers
15 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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0answers
15 views

Which analysis to use for ratio of events after/before diagnose, between positive diagnoses and negative?

I am trying to figure out what kind of analysis is needed to answer this kind of question: Is having a positive diagnosis in "D" changing the number of events "E" after the diagnosis? I want to ...
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0answers
19 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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0answers
2 views

Learning and quantifying feature contributions for differential expression in a case/control setting

I have a setting of a continuous response vector of expression Y of length N, that has also a case/control label for each measurement. In addition, I have an X matrix of features, NxP. I would like to ...
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2answers
97 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, ...
1
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1answer
44 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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0answers
35 views

Retrospective case study and inferential statistics

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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0answers
31 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 ...
0
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0answers
15 views

How to analyze data from two-tiered experiment

I have an experiment where each subject undergoes M sessions of treatment drug & control drug. I have N subjects. How do I 'match/pair' my data together? In particular, lets say that d(n,m) is ...
0
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1answer
21 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 ...
1
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0answers
15 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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0answers
25 views

Regression analysis (OLS) in matched case-control study

I have been asked to assist in a study based on samples of records from registers of dental care patients. My problem is that I would like to be sure that my proposed approach for the analysis is ...
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0answers
17 views

Exposure in Power Calculations

When estimating power calculations for a case control study, what does exposure of controls really mean? I find lots of information how how to calculate exposure for cases when you already know ...
1
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0answers
27 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 ...
0
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0answers
81 views

conditional logistic regression to analyze a case-control study

I am analyzing a case-control study on patient given dose effect to outcome (recovery or not). The control patients were matched according to age (5-year per category) and performance status (PS). As ...
0
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0answers
53 views

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 ...
3
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1answer
140 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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0answers
67 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 ...
8
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1answer
472 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 ...
8
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1answer
341 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 ...
6
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0answers
189 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 ...
1
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3answers
570 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
82 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 ...
2
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1answer
56 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 ...
1
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1answer
123 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 ...
1
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0answers
55 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
73 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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0answers
294 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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0answers
94 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 ...
4
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1answer
224 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 ...
6
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2answers
1k 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.
2
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0answers
372 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 ...
1
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1answer
62 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 ...
2
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1answer
194 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 ...
5
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2answers
142 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 ...
4
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2answers
265 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 ...
5
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1answer
1k 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 ...