Statistical Analysis Stack Exchange
Statistical Analysis Stack Exchange

Questions tagged [prevalence]

25 questions
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3 answers

Are thresholds for logistic regression models prevalence-specific?

I wonder if thresholds for logistic regression models are prevalence-specific. I assume that they are, however, I am not sure about the basic statistical principles behind it and how to deal with the implications for clinical practice. Example: A…
ava
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prevalence ratio question

I understand that prevalence ratio is Number of people in sample with characteristic Prevalence ratio = ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Total # of people in…
Science11
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Is there any form or program that generates prevalence ratio values ​through logistic regression?

When performing a binomial or multinomial logistic regression, odds ratio (OR) values ​​are generated. Is there any form or program that generates a prevalence ratio value instead of OR?
Anderson N. Barbosa
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question concerning Covid infection data reported by the media

I tried searching stackexchange for existing posts about this, but I could not find them. Please redirect me if appropriate. My question is very simple, and perhaps partly related to the observations made by several users in this post. Let me…
user6376297
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Prevalence threshold calculations error

I see on this page the formula for calculation of prevalence threshold: Given also are following values on that page: Sensitivity or TPR: 66.7% Specificity or TNR: 91% With these values, I am getting a prevalence threshold of 27%. However, it is…
rnso
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Correction for sample overlap in a meta-analysis of prevalence (metafor package)

I want to conduct a meta-analysis of around 30 studies (from a systematic review). Some background of the studies: The quantity of interest is the prevalence of RSV infection. Different studies reported RSV prevalence for different risk groups.…
bienco88
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Optimization of pool size and number of tests for prevalence estimation via group testing

I'm trying to devise a protocol for pooling lab tests from a cohort in order to get prevalence estimates using as few reagents as possible. Assuming perfect sensitivity and specificity (if you want to include them in the answer is a plus), if I…
Bakaburg
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How do i perform a meta-analysis of prevalence rates using metafor package (with no treatment group)?

I have a spreadsheet with this type of information: city cases population prevalence (per 100.000) lower_CI upper_CI chicago 20 10000 200 são paulo berlin I don't know…
Wellydo Escarião
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When comparing classifiers on different datasets with different prevalences, is it valid to calculate prevalence-adjusted PPV?

Scenario: comparison of 2 different binary classifiers Both classifiers report sensitivity and specificity and number actually positive (P), but classifier 1 is tested on a dataset with prevalence 20%, classifier 2 is tested on an enriched sample…
sideburns28
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Prevalence/proportion estimates: sampling/screening steps in different order make a difference for SE of the estimate?

We have a question that is quite puzzling but that will surely be something others have come across (e.g., in epidemiology). There are two methods we are thinking of to get a prevalence estimate, the question is, which one fits our aims, and are…
Anna Van 't Veer
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Compare geographical distributions of prevalences

I would like to ask you what statistical method should be used to compare two prevalence distributions. My problem is the following: I have two prevalences of two diseases A and B (non-exclusive) per 100,000 inhabitants for each region (n=100) of a…
docfak
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How does a small sample size (underpowered study) affect the prevalence?

I am doing a meta-analysis where I calculate an overall prevalence value for multiple studies. I have submitted my manuscript to a journal. I used sample size as one of the risk of bias criteria, where a low sample size represents an underpowered…
aspire94
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Pooled samples: estimating prevalence of disease

Struggling to understand the concept of pooled sampling and estimation of prevalence. Would really appreciate some help to understand this. Example: 0.5% of the population has a specific disease. Blood samples are taken on the same day from 3000…
TScott
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What is the difference between 1-year partial prevalence and annual incidence?

In cancer research, like in this article, partial prevalence is sometimes used to assess the epidemiological state of a disease in a population. The document I'm trying to understand (link, in french) gives total prevalence and partial prevalences…
Dan Chaltiel
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How to determine probability of a test result given the FPR and prevalence?

Person A is predicted to have a disease that exists within the population once for every 1000. The prediction has a FPR of 10% (1 in every 10 false cases is incorrectly predicted as being positive). How can I use this information to calculate the…
Ben
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