# Questions tagged [incidence-rate-ratio]

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### Interpreting categorical x categorical interaction in a poisson regression [duplicate]

I have run a poisson regression with two categorical predictors (treatment and disease severity) and their interaction, controlling for a number of relevant covariates. Treatment has two levels (...
4 votes
0 answers
507 views

### Are these negative binomial regression results reasonable?

I did a negative binomial regression on a data set with 4 covariables. The count outcome has values up to 600. I did a mixture model with 2 components, also called a latent class model. However, I am ...
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4 votes
2 answers
8k views

### How to calculate 95% CI for cumulative incidence rate using R?

for example, 30 events during 10000 person-years, the cumulative incidence rate is 3 per 1000 person-years, how to calculate its 95% CI?
1 vote
0 answers
280 views

### Modeling incidence rates in family-based cohort: Poisson vs Cox

I have a cohort made of family trios and affected sib pairs (probands have rheumatoid arthritis - RA). I would like to calculate some incidence densities (for example apparitions of RA, of disease 1, ...
1 vote
1 answer
93 views

### Relationship between survival time and incidence rate

I am working on an operations issue. We process patients in care and pay close attention to their discharge rate, which is more or less calculated as an incidence rate (discharges per 100 patients). ...
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1 vote
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### Can you calculate a standard error from confidence intervals?

Specifically, can I calculate a standard error from an incidence rate with known confidence intervals but no population size data?
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2 votes
1 answer
3k views

### How can I calculate a confidence interval for a rate ratio, if I only have the rates?

I want to calculate the 95% CI for an incidence rate ratio (IRR), but I only have incidence rates per 10,000. (I do not have counts for the 2x2 table.) Specifically, the incident rates were ...
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0 votes
1 answer
1k views

### Can I compute the p-value for a list of incidence rates?

Coming back to statistics after a long time, so please forgive any ignorance. I'm curious how I might be able to argue for statistical significance of a test. Specifically, I'm after a ...
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1 vote
1 answer
1k views

### How to compare two incidence ratios statistically- the rate parameter test

I want to compare two standardized incidence ratios (SIR) obtained in stratified analyses. I read in Mocci et al (2013) that they used the rate parameter test and cited the book Statistical models in ...
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2 votes
1 answer
1k views

### Calculating OR and IRR for a zero-inflated negative binomial model from estimates

I used the PSCL package to run a zero-inflated negative binomial model on some count data I have. This package gives the following output: for the zero part of the model: ...
2 votes
1 answer
192 views

### Using Chi-Squared for Google Analytics test?

I am running a test in Google Analytics to find the impact of a new functionality release for sharing stuff. The setup follows: There is a control group which continues to see and use the old "...
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2 votes
0 answers
1k views

### Calculating p-value from chi-square when comparing two incidence rates

I am trying to follow this guide to calculate the p-value from an incidence rate between two samples. The raw data is patients' use of an action plan before and after education. Before education 7 ...
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10 votes
2 answers
423 views

### Survival rate trends in case-control studies

I submitted an article which was rejected due to the improper way of performing the survival analysis. The referee left no other details or explanations other than: "survival analysis on time trends ...
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50 views

### Aggregating rates of events in a population

For every 100,000 people, 4 people succumb to event $X$, a different 10 to $Y$, and 2 others to $Z$. I would like to know the number of people that succumb to any of $X$, $Y$ or $Z$ per 100,000. Is it ...
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0 votes
1 answer
669 views

### Since incidence rate ratios are always positive, how does one determine the sign of the effect?

I want the results from a Poisson regression to be comparable to previous OLS and Tobit regressions. To do this, I am utilizing the irr (incidence rate ratio) option in Stata. However, since all the ...
• 153
3 votes
1 answer
5k views

### Interpreting negative binomial regression with log transformed independent variables

My independent variables were highly skewed, so to normalise the distribution they were log transformed. Also since there were zeros in the data, I've added + 1 to transform the variables. This is ...
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2 votes
0 answers
534 views

### Estimating mortality rates with direct age-standardization

I'm attempting to calculate the mortality rates of AMI (acute myocardial infarction) in patients (cases) with high bloodpressure, between the years 2001 to 2008. For every case I have 2 matched ...
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4 votes
0 answers
911 views

### Interpretation of log transformed predictor in negative binomial regression

I mainly want to make sure that I'm making the correct interpretation here. I built a negative binomial regression model predicting a count variable. There was evidence of overdispersion or I would ...
• 41
10 votes
1 answer
8k views

### Calculate incidence rates using poisson model: relation to hazard ratio from Cox PH model

I want to calculate incidence rates to present along hazard ratio's in order to present both relative and absolute measures of risk. I saw in other studies that such incidence rates can be calculated ...
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1 vote
0 answers
43 views

### Considering Age-standardized incidence rates: Will changing the reference population change the incidence rates [closed]

Im trying to calculate the mortality rates for males and females in two different disease groups (type 1 and type 2 diabetes). In my primary analyses i forgot to use respective gender as the ...
• 283
1 vote
2 answers
1k views

### Calculate confidence interval from point estimate and standard error

Im having a problem with calculating a confidence interval for an incidence rate ratio between two populations. Using PROC STDRATE from SAS, I've obtained the Incidence Rate Ratio (the difference in ...
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2 votes
3 answers
663 views

### How to prove that one variable's change is influenced by another variable; that is to say, are they related?

I major in bioinformatics. We all know that temperature changes during a year. I find that a disease incidence is really high when temperature is relatively high, while it becomes really low when the ...
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1 vote
0 answers
49 views

### Rolling twelve-month crime rate

I need to do a 12 month rolling crime rate. I have monthly crime counts and population counts every 3 months. For a calendar year I would usually use a population from mid-year as the denominator and ...
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3 votes
1 answer
2k views

### Comparing the ratios of occurrences

There are two groups: treatment control. Each group has three categories of outcomes: High medium and low blood pressure. The number of subjects is 100 for each group. Now, let's say, for ...
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6 votes
2 answers
2k views

### Comparing multiple incidence rates

I asked the following question on stack overflow yesterday: Negative binomial function in R Reading comment 2, I understand that I cannot use a negative binomial modeling approach (a Poisson model ...
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2 votes
0 answers
904 views

### How to calculate SE for the ratio of two proportions?

I have evaluated the prevalence (proportion) of a disease in men and women, in different studies available in the literature. So I have sample sizes for men and women (in different studies) and also ...
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6 votes
1 answer
2k views

### Incidence Rate Ratio (IRR) in R from linear regression using log-transformed data?

I was wondering if it would make sense to calculate IRR for OLS (not poisson), but the OLS is done using log-transformed data? I have a set of crude death rate data (which I'm still debating whether ...
2 votes
1 answer
968 views

### Inverse Incidence Rate Ratio

I wondered if it is possible to calculate the inverse of an IRR like we can for odds ratio (inverse = 1/x). For example: IRR = 1.40, 95% CI = 1.18 -1.65 Inverse IRR: = 1/1.40 = 0.71 Thank you (...
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1 vote
1 answer
160 views

### Simulation of woman's age of getting breast cancer (cumulative incidence rate)

I am writing a programme to simulate the age at which women will get breast cancer. I have data on the cumulative incidence rate for the whole population. What I am doing right now is using Monte ...
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0 votes
1 answer
2k views

### Comparing Incidence Rate Ratios

I am trying to compare incidence rate ratios (IRR). This is what I have: Group A (exposed vs. unexposed) IRR and Group B (exposed vs. unexposed) IRR So how would I correctly test for the ...
9 votes
3 answers
16k views

### Comparing incidence rates

I want to compare to incidence rate's between two groups (one without a disease and one with). I was planning to calculate the incidence rate ratio (IRR), i.e. incidence rate group B/ incidence rate ...
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0 votes
1 answer
2k views

### Negative binomial -- IRR interpretation for predictors

I have a zero-inflated negative binomial model. I have used incidence rate ratios and I'm trying to interpret the coefficients in relation to my predictors. Most of my predictors are continuous ...
4 votes
1 answer
733 views

### Alternative name for "incidence rate ratio"

I'm using a negative binomial GLM to predict individual level scores on a psychometric test that ranges from 0-27 and presenting the coefficient "incidence rate ratios". It seems a little strange to ...
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3 votes
2 answers
6k views

### Incidence rate ratios (Stata vs R)

I asked this question on Stackoverflow: https://stackoverflow.com/questions/8142118/incidence-rate-ratios-in-r-poisson-regression and was advised to post here instead. I have data that looks like ...
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16 votes
2 answers
33k views

### Interpretation of incidence-rate ratios

So, I want to fit a random effects negative-binomial model. For such a model STATA can produce exponentiated coefficients. According to the help file such coefficients can be interpreted as incidence-...
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4 votes
2 answers
8k views

### Is calculating Incidence Rate Difference/Ratio appropriate for single case experimental design?

(This is part-2 of my long question, you can have a look at part-1 here) I am going to do a quasi-experiment, with measuring the base line of a sample (actually not quite a sample, but a ward, with ...
• 3,039
9 votes
6 answers
3k views

### How to handle count data (categorical data), when it has been converted to a rate?

I am working on disease infection data, and I am puzzled on whether to handle the data as "categorical" or "continuous". "Infection Count" the number of infection cases found in a specific period ...
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