# Questions tagged [relative-risk]

The relative risk (also called 'risk ratio') is the quotient of the probabilities of an event under two conditions (ie, p1/p2). The RR has a possible range of [0, +infinity). It is a common measure of effect size in biomedical research.

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### Is combining Odds Ratios with Relative Risk in a Meta-Analysis Possible?

Can I combine ORs and RRs using generic inverse variance if the the event rare? There appears to be simple methods for converting ORs into RRs so would I do the conversion first and then apply the ...
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### Comparison of predictors in multinomial logit

I have been reading up on ways to understand variable importance in multinomial logistic so as to compare the predictors. My goal is to understand whether predictor A or B is playing a more ...
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### Relative Risk, confidence interval and sample size relationship

I'm following this example (see below for the source): Breast Cancer No Breast Cancer Total DDT exposed 360 13636 13996 Unexposed 1079 76313 77392 ...
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### odds ratio to relative risk equation, how is it derived?

How is this equation derived? thanks RR=OR/((1−Pref)+(Pref∗OR)) RR = risk ratio; OR = odds ratio; Pref = Prevalence of the outcome in the reference group
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### How we can obtain RR from case-control study through Poisson regression?

I found an article: https://link.springer.com/article/10.1007/s13300-020-00876-0 with case-control study design: "We conducted an open, multicenter, randomized, case-control study in a real-life ...
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### Is this how to convert odds ratio intervals to risk ratios

I have a binary logistic regression with just one binary factor predictor. I would like to report the 'risk ratio' (probability ratio) with a confidence interval. I'm using R 4.0.4 for statistical ...
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### I have calculated relative risk in SPSS with 95% CIs via a 2x2 table, but how do I then calculate the p value?

I have calculated relative risk in SPSS with 95% CIs via a 2x2 table, but how do I then calculate the p value? I thought I could use a two-tailed z test but can't seem to work it out
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### Am I misunderstanding Zou's method for computing relative risk for binary outcomes using Poisson regression?

It seems that relative risk estimation using Poisson regression is a popular approach in epidemiology, with a couple of papers I have recently looked at (for example  and many others like it) ...
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### Why the p-value of the interaction term changes when changing the link function of binomial Generalised Linear Model

I have fitted three binomial generalised linear models with three different link functions in order to investigate the relative risk/odds ratio/probability difference of the data. fiverelapse: an ...
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### Relative risk of mortality vs life expectency

I recognize that this is in part a subject-matter question, and not a statistics-only question, but it is one in which statisticians are sufficiently involved that I hope it is appropriate here. I am ...
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### Replicating STATA output for RR and confidence intervals based on marginal effects in [R]

I am working on replicating an output from STATA, with the following data where we want to obtain Relative risk and confidence intervals based on the marginal effects. I have been able to calculate ...
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### Is this study essentially using odds ratios in its calculation of “cumulative risk” of Alzheimer's dementia?

https://www.genomes2people.org/wp-content/uploads/2018/07/20020116_REVEAL_JAMA_Green_RiskDementiaAAWhite.pdf The above is a link to a Journal of the American Medical Association paper assessing risk ...
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### Converting Hazard Rate Ratio and Relative Risk to standardized effect size (eg Cohen's d)

We are 2 psychology students writing a systematic review. We need to convert the effect sizes from the different studies to Cohen's d (or another standardized effect size). Can anyone help converting ...
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### Estimating risk ratio instead of odds ratio in mixed effect logistic regression in R

glmer is used to estimate effects on the logit scale of y when the data are clustered. In the following model ...
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### How to tackle increasing survival probability?

I want to model probability of an event, which is typically modelled by survival methods. However, the predicted survival function is always non-increasing. My case is however opposite: The ...
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### Relative risk value depending on number of inherent risks and size of each inherent risk

If this is a beginner question, then I apologize in advance. I have a set of population with multiple risk factors: Every population member can have a combination of 30 different risk factors. Every ...
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### Confidence interval for relative risk with uncertain incidences

The usual suggestion for computing a confidence interval for a relative risk estimate is to start from the variance: $$\text{CI}_R = R \pm z \cdot \exp \sqrt{\sigma^2_{\log R}}$$ where $R$ is the ...
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### Can the Fisher exact test be used to get a confidence interval for the efficiency of a vaccine (risk ratio or relative risk)?

Consider the Pfizer vaccine for COVID-19. The data from the phase 3 trials shows that they had 21720 people in the vaccinated group and 21728 people in the control group: ...
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### Which statistical model is being used in the Pfizer study design for vaccine efficacy?

I know there's a similar question here: How to calculate 95% CI of vaccine with 90% efficacy? but it doesn't have an answer, at the moment. Also, my question is different: the other question asks how ...
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### How exactly is the “effectiveness” in the Moderna and Pfizer vaccine trials estimated?

As in the title. Is this "a risk ratio"? How is it calculated, if you could provide an example with numbers for both trials, please? I am not a statistician, but I am familiar with the ...
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### How to convert relative risk and confidence intervals/standard error to odds ratio and confidence intervals/standard error

I am conducting a meta-analysis and have one study which reports relative risks, and several studies reporting odds ratios. I would like to convert the relative risks to odds ratios and obtain ...
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### Am I using risk ratio appropriately?

I am doing a retrospective analysis of customers who renewed or terminated their subscription. I have about 40,000 renewals and 1,000 churn. Among my churn group, 25% (N = 250) contacted customer ...
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### Area-specific relative risks

I have a map with 12 areas and count data with some explanatory variables. I run a model and get the random effects intercepts. ...
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### Estimating the random effect structure and variance-covariance matrix for RRs from observational studies

long time reader, first time poster. Have found this community to be extremely helpful but alas have not had luck finding a previous question relating to this: I am attempting to run a meta-regression ...
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### Relative risk of interaction in Poisson regression model

I have fitted a poisson regression model for the problem: "How does the number of hours spent in an emergency room, revenue of the doctor and special training of the doctor influence the number ...
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### Stratified logistic regression with log link

I noticed the other day that I can mimic a stratified logistic regression using a meta-analytic approach at least when there is only one stratification variable with two different values. This is the ...
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### Calculating Risk Ratio: different results with different R-packages (epitools and epiR)

if someone could educate me on how R functions calculate risk ratios I would be grateful. I'm having trouble interpreting results from different packages: epitools ...
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### Are the confidence intervals and p-value for this risk consistent? [duplicate]

I'm trying to calculate a risk ratio with the following 2x2 contingency table, where the rows are exposure groups and the columns are disease status. The first row of the matrix shows that 1/38 ...
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### Relative risk not making sense for meta-analysis

I am doing a meta-analysis and struggling with the relative risk values. Looking at the forest plot and the RR for some relative risks I can tell it is incorrect. i.e first study rr should be 0.33. I ...
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### Can someone explain as simply as possible why you use OR in retrospective studies while using RR in prospective studies?

I've really tried to understand why you can't use RR in retrospective studies but for some reason I can't understand it. Has anyone been able to convey this simply to their students?
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### Reporting significance values for relative risk (RR) and number needed to treat (NNT)

I have calculated the relative risk & number needed to treat using the log-binomial regression model. NNT is calculated as the reciprocal of the marginal difference. Does it make sense to report ...
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### Why I estimate huge RR?

I am trying to do an excercise about temperature related mortality. I want to plot exposure-response curve, identify the temperature threshold and estimate Relative Risk of mortlaity above this ...
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### A regression model for ratio of two Binomial success probabilities

There are two series of observations of two Binomial trials. Observation $i$ of series 1 includes $n_{1i}$, the number of Bernoulli draws and $\overline{p}_{1i}$, the ratio between number of success ...
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### how do i calculate a population size weighted risk ratio?

I am a bit stuck. I have age startified risk ratios from published data from which i have sampled 10,000 iterations. I have a population census data of the population that i am going to apply the ...
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### How do you calculate a paired risk ratio and its confidence interval?

I have some data showing the number of times individuals make GP appointments at the week and at the weekend, over a period of about 5 years. The data also show the number of times each individual ...
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### Identifying risk factors in a study

I have a dataset of patients who have been inpatients (admitted to hospital) and not admitted (but visited as outpatients). Class proportion is 66:34. I have collected a list of features for all ...
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### Posterior of risk ratio as ratio of samples from posteriors of risks

I want to sample from the posterior distribution of a risk ratio. My idea is: define the posterior of risks $R_A$ and $R_B$) for two subgroups (e.g, exposed and non-exposed) in my data, using Beta(1....
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### What's “the clinically important absolute scale”?

In this article, the authors used the sentence "...risk difference (i.e., treatment effect on the clinically important absolute scale)". What did they mean by "clinically important ...
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### What's the interpretation of the ratio of the odds ratio between the experimental and the control arm?

Table 1 of this article show the associations between the outcome and variables, the authors presented the OR_ctr in control arm and ...
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### Conditions when the log of Relative Risk is approximately Normal

Under what conditions is the log of RR (or OR) approximately Normally distributed? Sources would be very much appreciated - wikipedia for example just states the SE formula but provides no information ...
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### Vertical translation of independent variable vs OR and independent variable vs RR curve

i have been trying to predict risk of developing a cancer from genetic data. At the end I plotted a curve, that shows odds ratio (OR) and relative risk (RR) as a function of polygenic risk score (PRS) ...
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### What is the relationship between the risk ratio and the weight of evidence? [duplicate]

I've been reading about risk ratios as typical measures in clinical settings. In the finance and credit literature, there is the weight of evidence (WoE) measure that is used to encode and study ...
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### How to calculate risk ratio for chemical substances

Simple example: Three different chemical substances are given to patients (each to 5 patients). Some patients die, some not. Samples (number of patients) are not equal. How to calculate the rate of ...
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### risk-ratio confidence-interval - but weighted?

I have survey data, with weights that adjust the sample to be nationally representative, from two time points. There is a binary presence/absence variable. Presence increases from time 1 to time 2. I ...
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### Interpreting the magnitude of the relative risk

I am used to interpreting Cohen's d in terms of small/medium/large effect sizes (cf. Cohen 1988 or Sawilowsky 2009) where, for example, a a Cohen's d of 0.2 corresponds to a small effect size. I am ...