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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Retrospective cohort study with case:control matching 1:5. Is clogit really appropriate?
I study school grades in children with brain tumors (=cases), using databases.
Every case in the database has five healthy controls, matched on sex, birth year and residency. The hypothesis is that ...
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Is it possible to have a hybrid case-control cohort study?
In a cohort study, you take 500 people and tell them to smoke cigarettes and you take 500 people and tell them not to smoke cigarettes: you then wait to see how many people in the future get cancer in ...
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Why marginal odds in frequency matched case-control?
Let $D$ denote sampling with $D=1$ indicating subject being sampled and $D=0$ otherwise. $W$ denotes intrinsic variable of subjects, $X$ denotes exposure of interest and $Y$ denotes the binary outcome....
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Case-control cox regression
I have a survival data on approximately 6 million observations.
The "failure" I'm dealing with is very rare - about 0.5% has the event of interest.
I have three questions:
Can I perform a ...
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Diff in Diff: wrong control group or wrong method?
I want to identify the causal effect of renewable energy targets on the environmental policy stringency index (I got it from OECD) for EU countries. My hypothesis is that by setting a renewable energy ...
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Creating a case-control cohort in R
I have a variable: hyperglycemia and a bunch of other variables like Age, Gender, BMI, many other variables. I would like to create a matched case control group case being those with hyperglycemia and ...
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Case-control study, odds ratio, logistic regression in Stata
I am very excited to be on this forum. I am new to biostatistics and have a question regarding my case-control study, for which I am using STATA for data analysis.
All my patients are diabetic. Some ...
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Which study design is best for the following?
I have a data set in which all patients have a particular disease. The disease has three varieties labeled as 0, 1, and 2 in the data set. I want to know the association of a particular drug with this ...
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Can selection bias lead to confounding bias?
I wonder if case-control matching will bring a new confounding bias into the matched design. In the following figure, $L$ is a confounder, $E$ is the exposure, D is the disease outcome. In the matched ...
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Is fixed-effects ordered logit models (feologit in Stata) suitable for matched case-control data?
Does anyone happen to be familiar with this method: fixed-effects ordered logit models (feologit in Stata)? In this paper: https://journals.sagepub.com/doi/pdf/10.1177/1536867X20930984
In the paper, ...
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What is the difference between these two methods of data collection?
I am trying to measure the effect of a campaign on the knowledge of a certain disease on population X
method 1: measure the same individual’s knowledge two times once before and once after passing ...
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Counterfactual modeling where variable is present in treatment but not control group?
I'm working with patient-level healthcare data in a pre vs. post difference-in-differences analysis where the goal is to estimate the average treatment effect for nursing care.
Patients in the ...
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Looking at how covariance/correlation between variables differs in two groups?
I have a few hundred variables representing different biomarkers. These variables have been measured in both cases and controls. The underlying units of measurement are not important, so I have ...
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Example 7.16 'Case-control study' in Cox, Principles of Statistical Inference
When reading Cox's Principles of Statistical Inference (CUP, 2006), I'm struggling with the case-control study example (Example 7.16, pp. 154ff.) in §7.6.6 on pseudo-likelihood.
Set-up:
Random ...
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Comparing treatment effects across groups
I created two donation campaigns, one loss framed (N:1993) and one gained framed (N:1989) I understood donations are usually veeeery low and the sample was a lot smaller than previously expected, so ...
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Best analysis for site selection with paired data
I'm running into a problem after trying what I thought would be a simple analysis. I have 47 sites where I measured a variety of habitat characteristics (canopy cover, habitat type, percent of bare ...
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Is it more appropriate to use random effect model in meta analysis when studies have high heterogeneity but they are not randomised?
I am using case control studies for a meta analysis. The participation selection is not random but the studies used different statistical analysis methods with their results and there is significant ...
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Selecting correct study design and statistical analysis for my project
I am analyzing risk factors associated with surgical site infections where we want to have a 3:1 case-control study. Other than some brief lectures in my classes, the only thing we were taught about ...
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Why is the fully-symmetric bidirectional case-crossover design biased and the semi-symmetric design not when there are time-trends in the exposure?
I am trying to understand why the fully-symmetric bidirectional case-crossover design is biased when there are time trends in the exposure and why the semi-symmetric design is not biased?
I have tried ...
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Members in treatment group serve as controls for other treatment members to eliminate unmeasured confounders in pre/post observational study?
Consider a typical observational healthcare study where pre/post health outcomes among patients receiving a treatment or care program are compared to a counterfactual control group who didn't receive ...
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Matched case control study design
I have a few questions about matched case-control study design. How do we handle matched case-control study design if you don’t have matched controls for all the cases? Would you remove unmatched case ...
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Statistical inference on the comparison of two UI mechanisms
Study context
We are running a study to compare two user interfaces where participants provide feedback on the binary classifications of an NLP classifier for bias (biased/not biased).
The goal of the ...
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Calculating the confidence interval or standard error of a PPV adjusted for prevalence
I am trying to evaluate how well a disease test performs in a case-control study. In this example, the prevalence is 0.5%, and the results are below:
Disease +
Disease -
Test +
40 (TP)
10 (FP)
Test ...
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Why we can apply conditional logistic regression to model the effect of air pollution?
In a book called 'Analysing Seasonal Health Data', the time series dataset - CVDdaily was expanded by 'casecross' function,
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Difference-in-differences analysis possible with only one data point per time period?
For example, total number of inpatient hospital visits during the 12 month pre-period and 12 month post-period per patient in each of the treatment and control groups.
Does a two data point data ...
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test for difference between matched pairs in 1:1 matched study
Background: I have a retrospective study (registry) that contains data on people with kidney transplant. Among these patients, we have a very small number of people with a specific genetic disease (n=...
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Problems due to sampling data from the same case patients multiple times?
Please imagine the following scenario: In a predictive modeling task for the probability that a hospital patient will encounter a certain medical event, all available data is split into cases and ...
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Propensity score matching in a case-control study: can the number of matches per patient be correlated with a matching variable?
Say I am trying to investigate the association between antidepressants and achieving recovery in a depression programme. I have an observational cohort of depressed patients enrolled in the programme ...
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Analysis of a continuous outcome for a treatment in a very small sample size (6 treatment, 5 controls) while adjusting for confounding variables
I have to assess changes in a continuous outcome after a treatment, however, my sample size is very small (6 treatment, 5 controls). Also, I need to adjust for 4-5 confounding variables such as age, ...
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Limits to how many control and treatment subjects may be paired in propensity score matching?
I'm working on a difference-in-differences project where we're matching up to 5 control subjects to each treatment subject using a combination of techniques to estimate treatment effects (ATT): exact, ...
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Balance diagnostics: Why not measure post-matching balance **within** matched treatment-control pairs?
I understand there are a number of techniques for evaluating post-matching balance at the covariate level: standardized mean difference (SMD), variance ratios, and empirical CDF statistics.
Are there ...
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Does "ds" have any statistical meaning?
I was reading a research paper and was wondering if "ds= .56 to .63" was a quantitative means of measuring the study, or if it was related to referencing?
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P-value of chi-square test of independence
I need help understanding chi2 independence test scipy.stats.chi2_contingency.
Let's assume I have two samples (of different sizes) of a categorical variable with 3 possible outcomes (1, 2, 3):
Counts ...
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Is parallel trends assumption necessary in difference-in-differences analysis?
Reading the literature on the subject, I haven't encountered clear reasoning why the parallel trends assumption must hold. In fact, there have been recent papers on ways to relax this assumption (see ...
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How to design experiment and holdout for two types of treatment at the same time
Let's say there are two types of treatment, namely treatment A and treatment B.
A subject can be in one of these categories:
get treatment A and then treatment B.
get treatment B and then treatment A....
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How to calculate sample size for a biomarker discovery nested case-control study (approach by M. Pepe)?
I'm about to design a nested case-control study in which I will try to identify a biomarker (or biomarker panel) from protein expression levels (determined with mass spectronomy).
I've got a cohort of ...
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Retrospective cohort study and case control study
What study would best suit looking at the association between low birthweight and later academic performance?
Note - 1000 low birth weight children and 3000 normal birthweight children were included ...
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Logistic regression for case-control studies
If I have designed a study where participants from 3 disease groups of fixed size were being sampled and suppose the three groups A, B and C are of sizes n_A=50, n_B=50 and n_C=100. Group A is a ...
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Extreme differences between control group and affected group
I am reviewing an article and cannot be overly specific but it involves one group of people with a medical condition and another group without it; the dependent variables are various mental health ...
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Interaction with a matching variable (time) in conditional logistic regression
Short version: I want to look at the interaction between an explanatory variable and a matching variable in my conditional logistic regression. Is that possible?
I'm doing a case-control study on risk ...
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Choosing control group for RCT
Imagine the following situation to illustrate my question:
We want to run an RCT to test whether policy2, combined with policy1, ...
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Can diagnostic accuracy measures be used in case-control studies?
I want to assess the predictive ability of biomarkers in a nested case-control study. The primary analysis with use conditional regression. I’d some questions:
1)Can I determine the AUC, sensitivity ...
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After the sample size calculation what is the next step in clinical trials?
Suppose I want to test if drug A is effective to reduce the levels of some disease. From previous studies, the drug is estimated to reduce the disease by 0.5 units (mean difference) with a standard ...
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Minimum sample size and power test
Suppose I have access to data on the energy consumption of a city with a population of 30000 persons. Imagine I want to test a new technology of smart energy, i.e if the energy consumption decreases ...
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Case-Control Study Design for Longitudinal Analysis
I am designing a study in which I want to examine the relationship between a disease - major depression - and five exposures of interest: healthy/unhealthy diet, daily exercise hours, general outlook ...
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How to combine the multiple days of a dose for meta analysis
I want to do a meta-analysis on case-control animal studies. But the problems is, a dose contain multiple days and shows their effects at each day like after 7, 14, 28 days. In a meta-analysis, I show ...
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Single SQL query for case-control matching [closed]
I am running a case-control study for which I wish to choose 5 controls for each case, stratifying by age, sex, and date of measurement. Each case or control has a unique serial number and the ...
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Statistical analysis for comparing expertise levels between 3 groups
I hope you are all safe and healthy considering the current climate.
I was wondering if someone could help with a statistical dilemma I have on my hands.
I am trying to explore whether IQ tests can ...
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Logistic regression, about 1 and 0'es
I'm doing a logistic regression in R and I'd like to know how to select the dependent and independent variables,
Logistic regression is done when the dependent variable of interest should be 1 ( like ...
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Case control sampling strategy for longitudinal analysis
Does it sound plausible to use a case-control sampling strategy to then address a longitudinal question?
For example, let's say I have a population of diabetics (N=100) and non-diabetics (N=9999). I ...
