The tag has no wiki summary.

learn more… | top users | synonyms

0
votes
0answers
22 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 ...
2
votes
0answers
23 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
votes
0answers
11 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
votes
1answer
19 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
vote
0answers
9 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 ...
0
votes
0answers
18 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 ...
0
votes
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
vote
0answers
25 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
votes
0answers
59 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
votes
0answers
35 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
votes
1answer
108 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 ...
1
vote
0answers
55 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
votes
1answer
282 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 ...
0
votes
0answers
17 views

Controlling for medication effects in case-control comparison

Say as an example problem you are comparing BMI between two groups, one group is healthy (CTL) and the other has been diagnosed with bipolar disorder (BPD). Some of the BPD patients are taking a ...
0
votes
0answers
23 views

Do I have to do McNemar test for each category or not?

I want to do a matched case control study where control group is matched to the case group by variables age and sex. Obviously the samples are not independent. Now my question is do I have to do ...
8
votes
1answer
299 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
votes
0answers
154 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 ...
0
votes
0answers
48 views

Why does increasing event weight in logistic regression increase c-statistic?

I have a logistic regression model that uses all events and a sample of non-events as the training and test population. The observation weights are chosen following King & Zeng. Events are ...
1
vote
3answers
409 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
vote
1answer
76 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
votes
1answer
49 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
vote
1answer
116 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
vote
0answers
45 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
votes
1answer
68 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, ...
1
vote
0answers
243 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 ...
4
votes
0answers
88 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
votes
1answer
207 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
votes
2answers
815 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
votes
0answers
336 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
vote
1answer
59 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
votes
1answer
179 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
votes
2answers
134 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
votes
2answers
257 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
votes
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 ...