Effect Size Calculator

The tool computes standardized effect sizes from study data to enable valid cross-study comparisons, meta-analyses, and transparent reporting. It targets researchers, data scientists, graduate students, and practitioners who compare two-group outcomes or binary results. You provide means, variances, and sample sizes for each group, or contingency data for odds ratios or risk ratios. The calculator returns one or more effect-size metrics (d, g, r, OR) with optional transformation to related statistics, enabling consistent interpretation across experiments and literature.
Conceptually, the system applies established statistical formulas: Cohen's d from group means and a pooled standard deviation, then applies a small-sample correction to obtain Hedges g. It also supports conversions between d, g, r, and OR where data permit, using standard mappings and logit transformations. For binary data, the tool computes odds ratios or risk ratios from 2x2 tables. All steps are deterministic, with explicit numeric results and auxiliary statistics such as standard error and 95% confidence intervals when inputs satisfy assumptions.
Users benefit from a single, auditable source of effect sizes that can be exported to reports or scripts. The tool reduces manual calculation errors, accelerates study screening and synthesis, and supports methodological rigor in teaching or applied research. It is suitable for psychology, education, medicine, social sciences, and marketing research where group differences and associations are central.
Core features include robust input validation, clear handling of missing data, and ready-to-export output in standard formats for reproducible workflows.