stan-dev / stan-dev/bayesplot

Visual Predictive Check

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feature new plot
Dominant language
R
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Avg merge
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Description

It would be great to have a so-called visual predictive check. To exemplify it I include an example in the form of a simple R script.

This plot is very useful for models which have continuous regressors which are given by the design of the experiemnt at the same value for all the subjects in a data-set. For example, imagine I have many subjects in a clinical study and one measures at pre-defined time-points for all patients whatever is of interest. The plot then allows to compare the raw quantiles of the data at each time-point vs what the model predicts for these quantiles (with its uncertainty).

vpc_example_R.txt

vpc_mtcars.pdf

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reviewing the linked vpc_example_R.txt script and vpc_mtcars.pdf to understand the requested visual predictive check and its expected output. Then inspect the repository's existing plotting entry points and tests to determine where this feature would fit. Done means a documented implementation reproduces the example's comparison of observed and model-predicted quantiles with uncertainty.

Written by the indexing model from the issue text.

Assessment

Tech stack
r
Domain
data-visualization
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
35/100

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