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Survey-Weighted Ratio Estimation

Source: R/analysis-ratios.R
get_ratios.Rd

Estimate the ratio of two survey-weighted totals (numerator / denominator) for a survey design object. Uses the delta method (linearization) for variance estimation for Taylor, SRS, calibrated, and two-phase designs, and direct per-replicate computation for replicate-weight designs. Both approaches are equivalent to survey::svyratio() for their respective design types. Supports optional grouping, domain estimation, and all five survey design classes.

Usage

get_ratios(
  design,
  numerator,
  denominator,
  group = NULL,
  variance = "ci",
  conf_level = 0.95,
  n_weighted = FALSE,
  decimals = NULL,
  min_cell_n = 30L,
  na.rm = TRUE,
  label_values = TRUE,
  label_vars = TRUE,
  name_style = "surveycore"
)

Arguments

design

A survey design object: survey_taylor, survey_replicate, survey_twophase, survey_srs, or survey_calibrated.

numerator

<tidy-select> A single unquoted numeric variable name for the numerator. Must resolve to exactly one numeric column.

denominator

<tidy-select> A single unquoted numeric variable name for the denominator. Must resolve to exactly one numeric column. All in-domain values must not sum to zero.

group

<tidy-select> Optional grouping variable(s). Combined with any grouping set by group_by(). Rows where the grouping variable is NA are excluded from all groups and do not appear in the output. This matches dplyr::group_by() semantics. Default NULL.

variance

NULL or a character vector from "se", "ci", "var", "cv", "moe", "deff". Controls which uncertainty columns appear in the output. Default "ci".

conf_level

Numeric scalar in (0, 1). Confidence level for confidence intervals. Default 0.95.

n_weighted

Logical. If TRUE, add an n_weighted column with the sum of weights for rows where both numerator and denominator are non-NA in each group. Default FALSE.

decimals

Integer or NULL. If an integer, rounds all numeric output columns (e.g., ratio, se, ci_low, ci_high) to this many decimal places. Default NULL (no rounding).

min_cell_n

Integer. Minimum unweighted cell count before surveycore_warning_small_cell fires. Default 30L (AAPOR guidance).

na.rm

Logical. If TRUE (default), NA values are excluded from analysis: observations where the analysis variable is NA are dropped from calculations, and observations where any group variable is NA are excluded from the output. If FALSE, NA observations in the analysis variable are included in calculations, and observations where a group variable is NA are collected into their own group row in the output (appearing after all non-NA group rows).

label_values

Logical. Accepted for API uniformity; has no visible effect on get_ratios() output. Default TRUE.

label_vars

Logical. Accepted for API uniformity; has no visible effect on get_ratios() output. Default TRUE.

name_style

"surveycore" (default) or "broom". When "broom", renames ratio → estimate, se → std.error, ci_low → conf.low, ci_high → conf.high.

Value

A survey_ratios tibble (also inheriting survey_result).

  • [group_cols...] — group variable columns (when active), first.

  • ratio — estimated ratio (weighted total of numerator / weighted total of denominator).

  • Variance columns (se, var, cv, ci_low, ci_high, moe, deff) — only those requested via variance.

  • n — unweighted count of rows where both numerator and denominator are non-NA.

  • n_weighted — sum of weights (only when requested).

Numerator and denominator variable names are stored in meta(result), not as output columns. Use meta(result)$numerator and meta(result)$denominator to access them.

See also

Other analysis: get_corr(), get_freqs(), get_means(), get_quantiles(), get_totals(), meta()

Examples

d <- as_survey(pew_npors_2025, weights = weight, strata = stratum)

# Ratio of prayer frequency to in-person attendance frequency
get_ratios(d, numerator = pray, denominator = attendper)
#> # A tibble: 1 × 4
#>   ratio ci_low ci_high     n
#>   <dbl>  <dbl>   <dbl> <int>
#> 1 0.871  0.808   0.935  5022

# With grouped estimates
get_ratios(d, pray, attendper, group = gender)
#> Warning: ! 1 cell has fewer than 30 unweighted observations. Estimates in these cells
#>   may be unreliable for public reporting (AAPOR guidance).
#> # A tibble: 4 × 5
#>   gender            ratio ci_low ci_high     n
#>   <fct>             <dbl>  <dbl>   <dbl> <int>
#> 1 A man             0.908  0.853   0.964  2194
#> 2 A woman           0.852  0.747   0.958  2758
#> 3 In some other way 0.953 -0.123   2.03     45
#> 4 Refused/Web blank 0.616  0.208   1.02     25

# AAPOR-compliant output
get_ratios(d, pray, attendper, variance = c("ci", "moe"), n_weighted = TRUE)
#> # A tibble: 1 × 6
#>   ratio ci_low ci_high    moe     n n_weighted
#>   <dbl>  <dbl>   <dbl>  <dbl> <int>      <dbl>
#> 1 0.871  0.808   0.935 0.0637  5022      5022.