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Questions tagged [diagnosis]

medical diagnosis: diagnostic accuracy and diagnostic research

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External validation of diagnostic model: Performance in subgroups

We are performing an independent external validation of a 2 published diagnostic risk prediction tools (logistic regression models) which estimate the risk for having a specific disease (model A and ...
b_surial's user avatar
  • 153
1 vote
1 answer

Generalized linear mixed model for assessing diagnostic accuracy of doctors

I am trying to determine how a doctor's expertise (either expert:1 or not an expert:0) affects their diagnostic accuracy of medical images. Additionally, I'd like to examine how the hospital at which ...
TobSignals's user avatar
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Evaluating the potential of a generic diagnostic test while incorporating baseline population prevalence

We have a dataset of 250,000 pregnant hospital patients who were admitted for delivery of the baby. Each patient was admitted only once to the hospital at the time of delivery and all medical ...
user3790522's user avatar
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Diagnosing cause of very wide confidence interval (in multivariate logistic regression)

I am trying to use Binomial Logistic regression to identify features from X-rays, which are associated with a disease state. The idea was to try get Odds Ratios for important radiographic features*. ...
Maks Hall's user avatar
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how to get the diagnostic power of more than one variable combined?

I have three antibody measurements to predict a condition. I am doing ROC analysis for each of the antibodies to check what is the diagnostic power for each one. But I want to try what is the ...
arshad's user avatar
  • 863
3 votes
1 answer

The different usage of ROC between diagnotic tests and machine learning

I am currently very confused about the ROC usage in diagnostic tests and machine learning. In the scenario of medical diagnostic studies, many tutorial does not mention the data split procedure as ...
Wei Fan's user avatar
  • 45
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P-curve analysis for meta-analysis of diagnostic accuracy study

I tried to do a meta-analysis of diagnostic accuracy study. I found out that I have a publication bias based on the Deek's regression test. Thus, I want to supplement my analysis with P-curve analysis ...
Tengku Hanis's user avatar
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Demonstrating that proposed cutoff score is non optimal

I have a small data set with a test score and classification (positive or negative diagnosis). There is already clinical evidence that the cut point suggested by the test manufacturer produces too ...
GuillaumeL's user avatar
1 vote
2 answers

Probability of disease in a patient with risk factor

I'm a doctor so I'm sorry for my basic knowledge of statisctics. I have a prior probability of the disease D $$P(D) = 0.12$$ I know that risk factor RF can cause the disease. Total probability of ...
Aliru's user avatar
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4 votes
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Correction for multiple testing required for combined metrics

Let's say I compare two diagnostic procedures (A and B) and want to check if one outperforms the other one using the metric diagnostic accuracy where diagnostic accuracy is commonly described using ...
snowman's user avatar
  • 41
1 vote
2 answers

Network meta-analysis of correlation coefficients: a logical paradox?

A colleague of mine wishes to conduct a network meta-analysis of correlation coefficients for a set of imaging tests (eg ultrasound, computed tomography, magnetic resonance imaging, and so forth). ...
Giuseppe Biondi-Zoccai's user avatar
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Assess sensitivity of a binary screening result across other continuous covariate(s)

I want to assess the sensitivity of a diagnostic screening test, which is a binary test (screen +ve and screen -ve). There is no continuous measure from this test - it is literally yes or no. My ...
Dilsher Singh Dhillon's user avatar
1 vote
1 answer

Post-hoc power calculation for AUC analysis, to evaluate a new diagnostic test in a cohort

I need some urgent advice for a grant application. I am evaluating a new diagnostic test and at the last minute a Professor has offered me the dataset from a completed prospective study of the disease ...
GhostRider's user avatar
1 vote
1 answer

Network meta-analysis of diagnostic test accuracy studies

I need to make a network meta-analysis of diagnostic studies. Is there a good explanation to do it with R?
Ahmed Mohamed Afifi's user avatar
1 vote
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Calculating sensitivity and specificity from survival data

I have a diagnostic test performed on 100 participants at baseline. I then follow up these participants for variable periods of time and have data regarding survival. I have used a Cox regression ...
RobMcC's user avatar
  • 211
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Handling incomplete information properly when using Bayes' theorem

Just for fun I'm trying to do some simple medical diagnosis using Bayes' theorem. Right now I'm calculating ...
haroba's user avatar
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1 vote
1 answer

Over-fitting diagnosis method

How much difference between train and test set errors can indicate over-fitting? For example in logistic regression. I am trying to classify 11746 comments based on their sentiments in three classes ...
keramat's user avatar
  • 201
2 votes
1 answer

Conflicting definitions of logistic regression

I do diagnostic research and am interested in determining how the probability of a patient having cancer is related to the concentration of different molecules in the blood. I have received ...
Christopher's user avatar
2 votes
1 answer

when add-on test is necessary? better diagnosis strategy

Suppose there are two types of tests available. Test A: low-cost, but relatively less precise; Test B: high-cost, but more precise. Test B can be considered as the good standard with 100% accuracy. ...
Joh's user avatar
  • 21
11 votes
5 answers

Interpretation of Bayes Theorem applied to positive mammography results

I'm trying to wrap my head around the result of Bayes Theorem applied to the classic mammogram example, with the twist of the mammogram being perfect. That is, Incidence of cancer: $.01$ ...
user2666425's user avatar
5 votes
2 answers

Which statistical model to use when trying to find the beginning of a time-dependent increase

I have a repeated measures data set with time as the independent variable and a single dependent variable, y. That is, for each subject, I have a certain (small, from 1 to 3) number of measurements. ...
January's user avatar
  • 7,349
4 votes
2 answers

What happens with sensitivity and specificity after a second test?

What happens with sens/spec and PPV/NPV if one performs a test twice (or three times etc.)? I will give an example from my own clinical practice. At many hospitals, we have a problem with ...
Johan_A_M's user avatar
1 vote
2 answers

Estimate ROC curve using binormal distribuiton

I am conducting a meta-analysis on diagnostic studies but for each study I have only mean and standard deviation reported. How can I estimate the ROC curve using the binormal assumption in R ? Tks,
Ellison F Cardoso's user avatar
2 votes
2 answers

Relationship between ROC curve and statistical significance in comparison of two groups

My question is about any possible relationship between the significance of a comparison test (Mann-Whitney U) and the ROC curve. If the comparison test is strongly significant, should we expect a ...
Panos's user avatar
  • 21