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# Tag Info

## Hot answers tagged incidence-rate-ratio

7 votes
Accepted

### Calculation of the Confidence Interval for Incidence Rate Ratio using Exact Approach

The authors of this study apparently carried out both univariate and multivariate stratified Cox proportional hazards models. They report hazard ratios with their 95% CI from the observed results (see ...
• 54k
5 votes

### Calculate probability of disease appearance

I personally feel this lends itself well to a survival analysis. You have people without moles in a certain hand at the start of the period (your at risk population); you can select these, and you ...
• 473
4 votes

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

This sounds like an incidence rate not cumulative incidence, which is a risk (number of cases divided by original disease-free population). Presumably the 95% CI for cumulative incidence is the same ...
4 votes

### Comparing two groups of incidence rates

If you want to compute a causal effect you need to control for confounders. The problem is, that you really need to find all confounders, otherwise your results are not reliable, and in the worst case ...
• 10.9k
4 votes

### Interpretation of incidence rate ratio

3,300 is wrong because you've simply multiplied the N of 10,000 by 1-IRR of to obtain 3,300. This would only be correct if everybody in the placebo arm was expected had Rota GE at least once by 60 ...
• 63.3k
3 votes

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

Use a Poisson GLM to do maximum likelihood under the assumption of independent interarrival times: ...
• 63.3k
3 votes

### Calculate incidence rate per person or in total

It's a simple rule that the sum of ratios is not the same as the ratio of sums. This is a result of Jensen's inequality. To really compare apples and oranges, you need to "average" out the second ...
• 63.3k
3 votes

### what is x per 100 person years mean?

Let's assume you followed 100 people. 50 of them you followed for 2 years and nothing happened. 25 newly developed the disease of interest after being observed for on average 1 year (not counting time ...
• 33.2k
3 votes
Accepted

### Incident rate ratios with log-transformed variables in Poisson regression

It seems this didn't generate any interest, so I'll answer with what I've found after a few weeks. IRRs are multiplicative, so: 'holding all other parameters constant, the change in ...
• 400
3 votes
Accepted

### Can odds ratio be in different direction to rate ratio?

You and the article are just looking at reciprocal ratios. $$(9/7129)/(795/306096) = 0.49$$ $$(795/306096)/(9/7129) = 2.06$$
• 178
3 votes
Accepted

### Incidence rates from manual calculation differs from that obtained from the estimated marginal means of a poisson regression

You are right that in this particular case the two approaches should give the exact same results (with some possible small differences in the confidence intervals). You had the wrong formula for the ...
• 33.2k
2 votes

### What type of statistical test should be used to compare successes of two treatments?

You have two treatments: drug A (hot) and drug B (cold). The Null- Hypothesis would be that cure rate (or proportions) of A equals to the cure rate of B. Null hypothesis: $p_{A} = p_{B}$ ...
• 308
2 votes

### What type of statistical test should be used to compare successes of two treatments?

This is a basic 2 by 2 frequency table. A chi-square test of independence would be appropriate. Also, you could use a risk ratio or odds ratio to describe the size of the effect and a construct ...
• 1,778
2 votes
Accepted

### Relationship between survival time and incidence rate

If all patients have the same constant risk of discharge, then you have exponential distribution of length of stay and average time of stay = 1/incidence rate. Or, to put it differently, if ...
• 391
2 votes

### Adjusting variable for covariate to calculate rates or metric

The report goes into their adjustment strategy a little bit, and in general your instincts are correct: when people talk about adjustment, they usually mean they're including those variables in a ...
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2 votes

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1 vote

### Incidence rate ratio after negative binomial results in R

Try this: exp(coef(Mymodel)) Mymodel is a model object containing much more than the fitted coefficients, and some of this ...
• 80.3k
1 vote

### Determining the statistical significance of change in incidence rates

Yes there is but you need less aggregated data. You now only have 5 data points which is usually not enough for statistical testing. Could you maybe get the monthly or even daily data? When comparing ...
• 93
1 vote

### Cumulative Incidence Rate in R Statistics

Hey @bvowe in terms of your first question, the result is ...
• 1,049
1 vote
Accepted

### What is the difference between 1-year partial prevalence and annual incidence?

This page from one of your links puts it pretty clearly: Partial prevalence is the number of all cancer patients, being alive at specific date (usually the last day of calendar year) and being ...
• 94.4k

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