Sample Size Calculators
Plan studies using calculators for power, precision, clinical trials, survival analysis, diagnostic accuracy, regression, and reliability.
Sampling and Randomization Tools
Generate reproducible samples and randomization schedules for research planning.
Generate reproducible sample numbers for simple random, systematic, stratified, and cluster sampling designs.
Generate reproducible two- to six-group schedules with unequal allocation, permuted blocks, and optional stratification.
Epidemiological Tools
Design-aware applications for describing disease frequency and estimating epidemiological associations.
Analyze a cohort, randomized-trial, cross-sectional, or unmatched case-control table using design-appropriate absolute and relative association measures.
Compare stratum-specific and crude binary associations with Mantel–Haenszel adjustment, conditional association testing, and odds-ratio homogeneity assessment.
Estimate an incidence rate from aggregate event counts and person-time, or compare two independent rates using exact Poisson inference.
Estimate prevalence, cumulative incidence, attack, mortality, case-fatality, or a single-population person-time rate using denominator-aware guidance.
Translate a binary-outcome risk ratio and target exposure prevalence into attributable, prevented, and counterfactual population-impact measures.
Diagnostic Accuracy, Reliability, and Agreement Tools
Applications for analyzing diagnostic classification, measurement reliability, and agreement between methods.
Analyze exact agreement and Cohen’s unweighted or weighted kappa for two raters using nominal or ordinal categories.
Estimate single- or average-measure ICCs and confidence intervals from complete balanced numerical ratings.
Analyze an aggregate binary 2 × 2 table with confidence intervals, likelihood ratios, and cautious interpretation.
Estimate additive bias, limits of agreement, and an exact normal tolerance interval from paired continuous measurements.
Fit standard or constant-CV weighted Deming and classical Passing–Bablok regression to paired quantitative measurements.
Questionnaire Development & Validation Tools
Applications for expert review, reflective measurement models, and questionnaire-development workflows.
Content Validity Index Calculator
Shiny appCalculate and explore content validity index measures for questionnaire, instrument, or expert-review studies.
Content Validity Ratio Calculator
Shiny appCalculate and explore content validity ratio measures for expert-review studies.
Calculate average variance extracted and composite reliability (coefficient omega) from reflective measurement-model loadings.
Generate response distributions, mean, standard deviation, missingness, skewness, and excess kurtosis from participant-level questionnaire responses.