Convert Nominal Dollars to Real (Inflation-Adjusted) Dollars

Adjusts nominal dollar amounts to real dollars expressed in a base year, using the bundled annual CPI-U series ([cpi_u]). The conversion is the standard `nominal * (CPI_base / CPI_year)`.

Usage

nccs_deflate(amount, year, base_year, cpi = NULL)

Arguments

amount

Numeric vector of nominal dollar amounts.

year

Integer vector of years the amounts are denominated in. Length 1 or `length(amount)`.

base_year

Single integer. The year whose dollars the result should be expressed in. Must be present in the bundled series.

cpi

Optional override. A two-column data frame with `year` (integer) and `cpi` (numeric); defaults to the bundled [cpi_u] table. Useful if you want to use a different deflator (e.g. PCE, GDP) or a custom snapshot of CPI-U.

Value

Numeric vector the same length as `amount`, in `base_year` dollars. `NA` for any input element whose year is not in the series; a single warning lists the missing years.

Details

For CORE Form 990 panels covering many years, deflating financial columns is usually a prerequisite for any cross-year comparison. This helper is a thin wrapper around vector arithmetic — it exists to (a) bundle the CPI lookup table so users don't have to fetch it themselves, and (b) standardize the lookup behavior (warning on out-of-series years, NA propagation).

See also

[cpi_u] for the bundled series.

Examples

# $100 in 1990 expressed in 2020 dollars
nccs_deflate(100, year = 1990, base_year = 2020)
#> [1] 198.0828

# Vectorized over a column
df <- data.frame(year = c(2010, 2015, 2020),
                 revenue = c(1e5, 1.2e5, 1.4e5))
df$revenue_real_2023 <- nccs_deflate(df$revenue, df$year, base_year = 2023)
df
#>   year revenue revenue_real_2023
#> 1 2010  100000          139735.7
#> 2 2015  120000          154268.4
#> 3 2020  140000          164824.1