Changelog

Source: NEWS.md

IQCC 0.8.0

New statistical methods

• Add the double-sampling np chart family for high-quality processes: dsnp_prob_accept(), dsnp_arl(), dsnp_ass(), dsnp_limits(), and cchart.DSnp().
• Add generalized variance monitoring through gv_stat(), gv_limits(), gv_alpha_risk(), and cchart.GV().
• Support normal, Cornish-Fisher, selected exact, and simulation-based limits for generalized variance charts.
• Add auxiliary multivariate variability monitoring based on tr(V) through trv_stat(), trv_limits(), trv_alpha_risk(), and cchart.trV().
• Add pure numerical u-chart functions uchart_limits() and uchart_alpha_risk().
• Add pure numerical p-chart functions pchart_limits() and pchart_alpha_risk().

Statistical corrections

• Replace the unweighted mean of subgroup proportions with the pooled binomial estimator in cchart.p().
• Replace the unweighted mean of subgroup rates with the pooled Poisson estimator in cchart.u().
• Correct standardized p and u charts so standardized statistics are not divided by subgroup size a second time.
• Audit the Cornish-Fisher p-chart implementation against the operational formulas and published numerical examples.
• Derive and validate CF1 and CF2 u-chart limits from Poisson cumulants.
• Correct the DS-np limit search so every candidate second-stage threshold is evaluated independently.
• Harden DS-np decision regions, probability calculations, ARL, ASS, and plotting.

Scientific validation

• Reproduce published p-chart false-alarm examples from Joekes and Barbosa (2013).
• Reproduce published DS-np ARL and ASS values from Joekes, Smrekar, and Barbosa (2015).
• Reproduce published generalized variance limits for dimensions two and three.
• Add independent numerical oracles for discrete DS-np probabilities and exact dimension-two generalized variance risk.
• Add property tests for tr(V), including its exact chi-square distribution, false-alarm risk, RNG preservation, linear-transformation invariance, and a same-determinant covariance change that is visible to the trace statistic.
• Add regression tests for scaling, monotonicity, boundary cases, invalid inputs, random-number-state preservation, and legacy aliases.

Documentation

• Add package vignettes on IQCC positioning, high-quality processes, and the statistical foundations of the audited methods.
• Add paper/statistical-foundations.md as article-oriented technical source material.
• Expand the README with scientific positioning, implemented methods, references, and development roadmap.
• Add documentation for all new public functions and S3 plotting methods.

Engineering and infrastructure

• Add GitHub Actions workflows for R CMD check, pkgdown, and test coverage.
• Add Codecov reporting and README badge.
• Expand automated tests substantially across legacy and new functionality.
• Separate numerical kernels from chart construction and plotting where audited.
• Improve input validation and replace silent string returns with errors.
• Remove examples based on attach() from audited interfaces.

Compatibility

• Preserve legacy p-chart aliases norm, CF, and std.
• Preserve legacy u-chart aliases norm, CF, and std; historical CF maps to the two-term Cornish-Fisher formula.
• Existing chart wrappers remain available while exposing new pure numerical APIs for reproducible calculations.

IQCC 0.7.1

Bug Fixes

• Fix d3() operator precedence bug: d2[1] was always used instead of d2[i], producing wrong results when called with a vector of sample sizes (#2)
• Fix stats() operator precedence bug: 1:m-1 evaluated as (1:m) - 1, producing index 0 on first iteration (affects all n=1 multivariate calculations)
• Fix cchart.T2.2() operator precedence bugs: is.null(x) == FALSE patterns were fragile (5 occurrences)
• Fix cchart.T2.1() incorrect UCL formula for Phase I with n=1: now uses correct beta distribution parameters per Montgomery 7th ed. (#1)
• Fix cchart.S() type parameter mismatch: code checked for "c" but documentation specified "e" for exact limits
• Fix cchart.Xbar_R() typo: add.stat corrected to add.stats
• Fix standardized p-chart and u-chart: removed erroneous multiplication by sample size
• Fix cchart.T2.1() error handling: sprintf() replaced with stop()
• Fix error messages throughout: return("msg") replaced with stop("msg")
• Correct spelling in standardized, Shewhart, and approximation documentation.
• Add input validation (n >= 2) to d2(), d3(), c4()

Documentation

• Fix 11 typos across R source files
• Fix 3 broken examples (missing required sizes argument)
• Fix 8 inaccurate @param/@return descriptions
• Export previously unexported cchart.Xbar() function
• Add comprehensive roxygen documentation for cchart.Xbar()

Code Quality

• Create constants.R with ALPHA, SIGMA_MULT, Q_LOWER, Q_UPPER constants
• Replace 15+ hardcoded magic numbers across 7 files
• Standardize T/F to TRUE/FALSE throughout
• Standardize = to <- for assignment
• Replace is.null(x) == FALSE with !is.null(x)
• Fix table.qtukey(): remove unnecessary function definitions, add invisible() return
• Pre-allocate vectors in d2() and d3() (was O(n²) with append())
• Replace matrix(nrow=m, ncol=1) with numeric(m) for control limits

Infrastructure

• Move miscTools from Depends to Imports
• Replace blanket import() with selective importFrom() directives
• Update minimum R version to 3.5.0
• Add Language: en-US to DESCRIPTION
• Clean up .Rbuildignore and .gitignore
• Update README with usage examples and feature overview

Testing

• Create testthat test suite with 8 test files and 53 tests
• Add tests for all exported functions
• Add input validation and edge case tests