Is a reported percentage consistent with its count?

percentage_of() checks whether percentage is what absolute out of n would have been reported as, given the number of decimal places and the rounding method.

This is stricter than grim() with x_meaning = "percentage", which only asks whether some count out of n produces the percentage. Here, the count is reported too.

The function is vectorized, but percentage_of_map() is more convenient for testing many cases.

Usage

percentage_of(
  absolute,
  percentage,
  n,
  digits_percentage,
  rounding = "up_or_down",
  threshold = 5,
  symmetric = FALSE
)

Arguments

absolute: Integer. The reported count.
percentage: Numeric. The reported percentage of n that absolute is said to be, e.g., 33.3.
n: Integer. The reported total.
digits_percentage: Integer. The number of decimal places in percentage, including trailing zeros. There is no default, since a numeric value does not keep them (1.40 is 1.4).
rounding: String. The rounding method assumed to have produced percentage. Default is "up_or_down", which accepts either direction. See grim() for the other methods.
threshold: Numeric. For rounding = "up_from", "down_from", or "up_from_or_down_from", the point within a step at which rounding switches direction, in tenths of a step. Default is 5. Ignored otherwise.
symmetric: Logical. If TRUE, negative numbers are rounded like their absolute values (-2.5 like 2.5) under "up", "down", and the "*_from" methods. Default is FALSE. Must not be TRUE with a "ties_*" rounding method, which already fixes the direction; see roundwork::reround().

Value

Logical. TRUE if the three values are consistent, FALSE if not, and NA if the case cannot be decided: if a value is infinite, if absolute is not a non-negative whole number, if n is not a positive whole number, or if a missing value could decide the case either way. A missing absolute gives FALSE if no count out of n has the percentage, and a missing n gives FALSE if no n makes absolute that percentage. A missing digits_percentage is treated as in grim().

Details

The test runs in exact integer arithmetic. absolute, percentage, n, and digits_percentage are vectorized; all other arguments must have length 1.

An absolute above n is tested like any other, as for answers to a question that allows several, whose percentages can sum to more than 100.

Causes of inconsistencies

A FALSE result means that the three values cannot all be correct as reported, but not why. The cause is often trivial: the percentage may be based on another denominator than n, such as the number of valid responses, or on an unconventional rounding method. percentage_of_map_seq() with var = "n" shows which nearby denominators would make the percentage consistent.

Examples

# 40 out of 120 is 33.33...%, so it can be
# reported as 33 or 33.3, but not as 34:
percentage_of(40, 33, 120, digits_percentage = 0)
#> [1] TRUE
percentage_of(40, 33.3, 120, digits_percentage = 1)
#> [1] TRUE
percentage_of(40, 34, 120, digits_percentage = 0)
#> [1] FALSE