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Questions tagged [odds-ratio]

A measure of association between two binary variables equal to the odds of a 'positive' outcome in 1 variable divided by the odds in the other. The OR ranges (0, infinity). It has a strong connection to logistic regression.

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23 views

How to express the uncertainty in the OR of a right-tailed Fisher's exact test?

Many OR (odds ratio) visualizations show 95% confidence intervals expressing uncertainty like on the left panel in figure below. However, in genomic overrepresentation analysis right tailed Fisher ...
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1 answer
901 views

Multivariate Analysis and AOR

Given Table 3, I understand how to calculate the Bivariate analyses in Table 4. But how do I calculate Multivariate analyses using AOR? Are there any formulas to calculate these?
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How to find difference between two hazard ratios (ratio of hazard ratios)

I am reading a meta-analysis and in this paper the authors somehow compared HR from two groups with different treatments in each study. As I know, we can compare outcomes from two groups with ...
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Is there an way to model random effects in a design that is typically analyzed by the McNemar test?

My question is: if in a study with paired binary response data (where McNemar test is often used) we can use the exact binomial test to test the odds ratio, is it possible to model the same odds ratio ...
3 votes
2 answers
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Summarizing ratios in a systematic review - does any joint effect measure exist?

I am responding to reviewer comments on a systematic review summarizing a number of risk factors. The exposure is any risk factor (this is what I am trying to make an overview of) and the outcome is ...
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2 answers
751 views

How to interpret OR confidence intervals for interaction or confounding?

This is a textbook problem I've been trying to understand I wanted to check if my thinking is correct (unfortunately there is no solution manual) I have a case-control study where I'm looking at ...
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logit model - labor probability(odds ratio) [duplicate]

The logit model is given: $$ \text{Labor probability} = \alpha + \beta_1 \cdot \text{income} + \beta_2 \cdot \text{age} + \beta_3 \cdot \text{education} + \beta_4 \cdot \text{young kids} + \beta_5 \...
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1 answer
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What are the issues with absolute risk reduction/relative risk reduction vs odds ratios in reference to variation over risk factors

The following quote is from this: Any measure that has the potential for summarizing a treatment effect with one constant for all types of patients will be non-collapsible when the outcome is ...
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How does one compute the posterior odds ratio between two models

Apologies if this question has been asked before but I couldn't find anything that matched my problem. I have some astronomy based data sets and wish to find which of three models fits the data the ...
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342 views

How to interpret odds ratio output for when there are multiple categorical dependent variables

I am doing a project assessing whether a radiological abnormality called CSP is more common in brains of people with dementia compared to healthy controls. The size of the CSP is important so I have ...
7 votes
1 answer
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Why is the Bayes factor sometimes considered more important than the Posterior Odds?

To the best of my knowledge, the posterior odds satisfies the equation: $$(\text{posterior odds}) = (\text{Bayes factor}) \times (\text{prior odds}) $$ This is a simple consequence of Bayes' rule. The ...
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1 answer
474 views

Test for proportions - which one to choose?

I have a general question regarding proportions. Let's say, for simplification of things, that I have 2 groups of subjects (treatment and control), and for each subject I measure success or failure (0 ...
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Plotting interaction by logistic regression

I have used R to plot the interaction term from the logit function I computed. I use the standard cat_plot() to plot the interaction. I clearly see that the two ...
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How to convert odds ratio to cohens d [duplicate]

I want to calculate the cohens d from adjustad OR, but I think I'm doing something wrong. If aOR = 1.79, N = 600, N_case = 298, N_control = 302, then is the cohen's d 0,139 or 0,321? What formula did ...
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Test of homogeneity for Odds Ratios in conditional logistic regression analysis SPSS

I'm doing a case-control study, and I have made stratified analyses based on two age groups, as well as subtype of the type of cancer I'm doing my research on. My exposure of interest seems to be ...
4 votes
1 answer
118 views

Sample size calculation for proportional odds model

Apologies in advance for my lack of statistical knowledge/insight! I am trying to calculate the sample size for a clinical trial of treatment A versus placebo with primary outcome of prolongation of ...
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Binary logistic regression: why do these two coefficients have opposing signs when they are indicators of the same outcome?

I hope someone can help me understand why this is happening. Reproducible example in R: ...
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1 answer
234 views

Relationship of a negative coeffecient and positive odds ratio in an ordered logistic regression

I am wondering about the relationship and interpretation of the regression coefficient and odds ratio (OR) of an ordered logistic regression. I know the OR will always be positive given the ...
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Meta-analysis of odds ratio for continuous variables, how to interpret the decrease or increase per unit?

So, I am doing a meta-analysis of odds ratios to find out the risk factors for a certain medical outcome. One of those risk factors would be (simplified) the time spent in the operation room. My ...
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Estimate subgroup sizes with a a given OR including CI and total sample sizes

We are doing a meta-analysis using OR as the effect size, but on a limited number of trials. The data is a bit messy and some numbers are missing - at least for our purposes. I was wondering if there ...
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Checking my interpretation of the odds ratio in OLR [duplicate]

I have run an ordinal logistic regression (response variable is "classification" with three ordered levels: control, intermediary group, and disease group). The predictor variable is a ...
7 votes
1 answer
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What is the best statistical test to compare the survey Response rate for a control and treatment group?

We run a survey and want to run a controlled test on a sample of the data. The measure we are trying to improve is response rate. Our research question is: “does sending out more invites to ...
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3 answers
521 views

Interpreting a very small odds ratio when the Fisher's exact test is significant

I'm having a hard time interpreting odds ratios (OR) for a 2x2 contingency table. ...
2 votes
2 answers
124 views

How do I interpret & present Meta Analysis Report to Non-Statisticians?

I have a Meta analysis report & I have to present the findings of the report to non-statisticians. There are 2 treatment groups & 5 endpoints. How do I explain pooled odds ratio, forest plot,...
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3 answers
624 views

Odds Ratios paradox? Pooled OR inconsistent with subgroup ORs

I have two groups (A and B) that each produce ORs of 1.44 and 1.50. However, if I combine the frequencies for the two groups to create a pooled dataset, I get an OR of 1.40. I get that it's not going ...
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determining if odds-ratio for a numerical x variable and binary y label in logistic regression differs between groups (ie. gender or race) [duplicate]

I've seen people ask a similar question, but I'm still not super clear what the best recommendation would be - I am looking at a binary dependent variable, and multiple independent variables (some of ...
1 vote
2 answers
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Scaling the odds-ratio of a binary logistic regression

Just a quick one - to put it simply, I am conducting a study regarding age and marriage. I have found that with a binary logistic regression (dependent variable yes/no to being married), the odds-...
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1 answer
415 views

Odds ratio interpretation for generalized additive models

This is probably a very crude question and I've been thinking about it for a while. Is the odds ratio the same for generalized additive models (GAMs) as it is with generalized linear models (GLMs)? If ...
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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 ...
2 votes
1 answer
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Same odds ratio for both rows and columns

I'm getting stuck on how to run the odds ratio test for these two different questions: Novice clinicians are more likely to use validated assessments than other assessments Novice clinicians are ...
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Binomial logistic regression and inter-group comparison

I am interested in exploring the relationship between two categorical variables: "Ethnicity" and "Disease", each with two levels. My primary hypothesis is that individuals with &...
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Odds Ratio - how many times more likely?

Problem: I need to figure out how many times are women more likely to continue attending a class after a certain period of time. Data: Solution: I used odds ratio (see picture). Is it correct to ...
1 vote
1 answer
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SPSS: GLMM and(adjusted) odds ratio

I am performing a retrospective study and the relative statistic analysis. I am studying the the risk factors for the occurrence of complications during medical procedures. I have 50 subjects ...
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Can you derive the standard error of odds ratio, from a method (Kraemer and Kupfer) that derives Risk Difference (and its SE) from continuous data?

Let's say that we have a RCT trial going on and the outcome is a continuous variable. In this paper https://pubmed.ncbi.nlm.nih.gov/23045205/ there are 4 methods that calculate approximated odds ...
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interpreting logistic regression output: how to relate predicted values to coefficients [duplicate]

I see many questions on this topic, but I promise none seem to explain what I'm after. I want to understand how to tie the coefficients I get from a logistic regression model back to the model ...
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1 answer
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Interpreting odds ratio units

I'm running logistic regressions in Python using statsmodels logit and, downstream, am calculating odds ratios for each independent variable. I know that, conventionally, an odds ratio is interpreted ...
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Odd ratio for binomial variable values

I am calculating the odd ratio of logistic regression (using statsmodel of Python). I have one independent variable (i.e. process type: faulty (1) or non-faulty (2) and one dependent variable (i.e. ...
4 votes
2 answers
259 views

Calculating odds ratios for an interaction term

Ratgrp stands for lung function (FEV1/FVC)*100 and it has two categories: 1: Lung function less than 70 2: Lung function equal and higher than 70 ...
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2 answers
1k views

Very small Cramer's V and moderate Odds Ratio?

I'm running a Chi Sq test with 2 binary variables. The data are large (>1 million rows) and not balanced (rare event). The test is statistically significant (p < .0001) and the Cramer's V is ...
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Can I add up odds ratios for specific predictors?

I have a cohort of patients for which I have 2 separate polygenic risk scores. I would like to produce a quantile plot such as this one: To do so, I have first divided the PRS score into quantiles, ...
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Odds ratio direction changes in multinomial logistic regression

I am doing a multinomial logistic regression in R for an outcome variable with four categories, and 9 categorical independent variables. My dataset contains 1408 observations. When I run the model ...
2 votes
1 answer
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Interpreting Fisher's exact test OR, CI and p-values

In the context of Fisher's exact test results, it seems that a bunch of online tutorials mainly focus on interpreting the p-value exclusively, without considering the confidence intervals or the odds ...
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Crude multivariate binomial regression OR vs univariate binomial regression OR?

I've performed an univariate binomial regression with OR (95% CI) and I obtain this result: ...
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Is it possible to give a single Odds Ratio for two independent variables?

I have been asked by co-authors on a paper to fill in the Odds Ratios marked as (?) in a table like the one below. Country of origin Land A (Odds Ratio) Land B (Odds Ratio) Number of people who meet ...
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3 answers
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Logistic regression: restrict the prediction range [duplicate]

I am running a basic logistic regression with a single independent variable (X) and one dependent variable (y). In the accompanying figure, the logistic regression predicts values that tend to 0 and 1 ...
2 votes
1 answer
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Ordinal Logistic Regression SPSS Interpretation

I have data from a questionnaire study structured like so: Age - Ordinal (18-24, 25-34, 35-44, 45-54, 55+) Gender - Nominal (Male, Female) AnxietyType - Nominal (Self-diagnosed, Professionally ...
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Comparing significance of categorical levels in logistic regression

I'm running a logistic regression on some data that has a binary outcome and several input variables, one of which is categorical with 5 levels. I'm using one of these levels as the reference, and so ...
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Find the impacts of alleles on the intensity of a disease

I have a dataset, I attach a sample of my data and the code. I have one column which shows the intensity value of a disease, one column which shows that its weak of moderate and the other columns are ...
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Modelling of odds ratio with continuous & categorical covariates

We've completed a systematic review of % diagnosed among female sex workers (FSW) living with HIV across Sub-Saharan Africa (SSA). In our Objective 1, we model this proportion $p_s$ as: \begin{aligned}...
5 votes
1 answer
363 views

Why Do We Need Relative Risk?

I am an MBA student that is taking courses in statistics. In our classes, we are learning about Odd's Ratios and Relative Risk. Our Prof outlined the following examples: Example 1: Suppose we take a ...

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