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Compare an R-built dataset against a SAS oracle

Source: R/compare_built.R
compare_built.Rd

Joins r to oracle on id and classifies every variable. Row-set differences are reported separately from value differences: an identifier present on one side only is a cohort discrepancy, a different class of problem from a miscomputed variable, and conflating the two hides both.

Usage

compare_built(oracle, r, id = "ccfidu", tolerance = 1e-08)

Arguments

oracle

Data frame read from the parquet oracle. See snapshot_oracle().

r

Data frame produced by the R pipeline.

id

Name of the identifier column present in both. Must be unique within each.

tolerance

Numeric. Absolute numeric differences at or below this are reported as "within_tolerance". A single absolute threshold cannot serve columns of very different magnitude; see the "Coming from SAS" vignette for how to read max_rel_diff alongside it.

Value

An object of class built_comparison: a data frame with one row per variable and columns variable, n_common, verdict, n_differ, max_abs_diff, max_rel_diff, and detail. n_common is the number of rows compared (constant across all rows, so it survives write.csv() or as.data.frame(), unlike the rows attribute). verdict is one of "identical", "within_tolerance", "differs", "absent_in_r", "absent_in_sas", or "type_mismatch". The rows attribute holds a list with n_oracle, n_r, n_common, only_oracle, and only_r.

Details

This function deliberately returns a table and never a single pass/fail. Collapsing several hundred variables into one boolean launders real differences into a green check. Read the table.

A difference does not automatically mean the R code is wrong. SAS orders missing numerics below all values, so if bmi < 18.5 classifies a missing BMI as underweight where R yields NA. Record such cases as intentional_divergence in equivalence_signoff.yaml.

See also

snapshot_oracle()

Examples

o <- data.frame(ccfidu = c("A1", "A2"), age = c(65, 70))
r <- data.frame(ccfidu = c("A1", "A2"), age = c(65, 71))
compare_built(o, r, id = "ccfidu")
#> Dataset comparison
#>   rows: 2 oracle, 2 R, 2 common
#> 
#>   variables by verdict:
#>     differs            1
#> 
#>   requiring review:
#>  variable verdict n_differ max_abs_diff max_rel_diff detail
#>       age differs        1            1   0.01408451