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0answers
41 views

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?
0
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1answer
40 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 ...
0
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1answer
24 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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0answers
12 views

Sample size for incidence rate (based on relative error)

I have a problem with sample size estimation for incidence rate based on relative error. There is a sample size formula on two published books one of them a book from WHO (sample size determination ...
0
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1answer
51 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: ...
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0answers
33 views

Shall we age-adjust when we do yearly incidence trend analysis?

I have datasets for years 2002-2011 and I want to examine the trend (using chisquare) of having a specific reversible condition every year. The dataset is inpatient admissions sample. Assuming the ...
2
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0answers
125 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 ...
0
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0answers
50 views

Poisson distribution vs Three-way table to Compare multiple incidences

I need some help understanding the difference between comparing incidences of rare events with a Poisson distribution and using a three-way contingency table. I'm sure I have some fundamental ...
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0answers
28 views

R survreg returns reciprocal of incidence rate ratios?

I'm working through some poisson regression for survival data using R. As I understand it, the exponentiated output from survreg with dist = "exponential" should give the incident rate ratios. I ...
8
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2answers
196 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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0answers
18 views

High Value of Incidence-Rate Ratio

after running several negative binomial models, the IRR for one of my ivars has returned consistently high IRR values ranging from 18 to 365.... All the other ivars return 'normal' IRR values and I am ...
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0answers
37 views

Incidence rate in a cohort with small sample size

I am dealing with the following problem: I have a small cohort of people with a specific disease (n=300) and studying the incidence of a related disease (which is kind of rare and normally occur only ...
0
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0answers
70 views

Poisson/Negative Binomial/Gamma log-link for continuous dependent variable (scale DV)

In my research about sport injuries in football, I am trying to obtain Incidence Rate Ratios (IRR) comparing my categories with the reference category. I have number of days a player was absent due to ...
0
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0answers
14 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 ...
2
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1answer
579 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 ...
2
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0answers
156 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 ...
3
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0answers
207 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 ...
6
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1answer
1k 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 ...
1
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0answers
24 views

Considering Age-standardized incidence rates: Will changing the reference population change the incidence rates

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 ...
1
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2answers
499 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 ...
2
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3answers
209 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 ...
1
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0answers
33 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 ...
2
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2answers
956 views

Comparing the ratios of occurrences

I am trying to find a statistical test for comparing the ratios of occurrences and would appreciate any help. There are two groups; treatment and control. Each group has three categories of outcomes; ...
5
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2answers
439 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 ...
2
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0answers
238 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 ...
5
votes
1answer
518 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
1answer
278 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 ...
1
vote
1answer
95 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 ...
0
votes
1answer
567 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 ...
8
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3answers
5k 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 ...
0
votes
1answer
479 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 ...
3
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1answer
387 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 ...