README.md

In baselinr: WWC-Aligned Baseline Equivalence Tables for Education Impact Evaluations

baselinr

baselinr builds report-ready baseline equivalence tables for impact evaluations in education research, following the conventions of the What Works Clearinghouse (WWC). Given a treatment indicator and a set of covariates, it reports the appropriate standardized effect size — Hedges’ g for continuous covariates, the Cox index for binary ones — and the WWC equivalence category for each.

It is a thin, education-specific reporting layer. For general-purpose covariate balance assessment, see cobalt; baselinr focuses narrowly on the WWC equivalence categories that education evaluation reports are required to state.

Installation

# install.packages("remotes")
remotes::install_github("zl1212-ship-it/baselinr")

Example

library(baselinr)

study <- data.frame(
  treat   = c(1, 1, 1, 0, 0, 0),
  pretest = c(5, 6, 7, 4, 5, 6), # continuous -> Hedges' g
  female  = c(1, 0, 1, 0, 0, 1)  # binary     -> Cox index
)

knitr::kable(baseline_equivalence(study, treatment = "treat"), digits = 3)

| covariate | type | n_treatment | n_comparison | mean_treatment | mean_comparison | sd_treatment | sd_comparison | effect_size | wwc_category | |:---|:---|---:|---:|---:|---:|---:|---:|---:|:---| | pretest | continuous | 3 | 3 | 6.000 | 5.000 | 1.000 | 1.000 | 0.80 | not_satisfied | | female | binary | 3 | 3 | 0.667 | 0.333 | 0.577 | 0.577 | 0.84 | not_satisfied |

The WWC categories are:

| Effect size (absolute) | Category | Meaning | |----|----|----| | <= 0.05 | satisfied | Baseline equivalence holds. | | 0.05–0.25 | satisfied_with_adjustment | Holds only if the covariate is adjusted for in the impact model. | | > 0.25 | not_satisfied | Cannot establish equivalence. |

Visualise and format

love_plot() shows the standardized effect size of every covariate against the WWC thresholds (requires ggplot2):

love_plot(baseline_equivalence(study, treatment = "treat"))

gt_baseline() renders the same table as a formatted gt table for reports and Quarto/HTML (requires gt):

gt_baseline(baseline_equivalence(study, treatment = "treat"))

Scope

Continuous covariates use Hedges’ g (with the WWC small-sample correction); binary covariates (numeric 0/1, logical, or two-level factor) use the WWC Cox index. wwc_summary() collapses the table into an overall verdict, and attrition() reports overall and differential attrition. See NEWS.md for the roadmap.

License

MIT © Yuxia Liang

baselinr documentation built on July 8, 2026, 9:07 a.m.