# Questions tagged [diagnosis]

medical diagnosis: diagnostic accuracy and diagnostic research

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### 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: $.01$ ...
246 views

### 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. ...
42 views

### 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 ...
249 views

### 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 ...
829 views

### 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 ...
28 views

### 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 ...
21 views

### 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. ...
336 views

### 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 ...
82 views

### 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). ...
200 views

### 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?
458 views

### 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,
402 views

### 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 ...
77 views

### 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 ...
8 views

### Estimating a learning curve without gold standard

Consider the outcome of a diagnostic tool in medicine: each patient has either the disease or is disease-free (0/1). Now, let's further assume that it is not possible to have a false-positive, i.e. ...
22 views

### How to calculate the reclassification calibration statistic (RC statistic)?

In risk prediction models there is a need to evaluate the added diagnostic value of a new variable (biomarker). Different measures have been suggested, among them there is the reclassification ...