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Do two sources agree?

Source: R/sources.R
compare_sources.Rd

Fetch the same indicator from several providers and put the answers side by side. Sources disagree more often than people expect – different vintages, PPP bases, territorial definitions, revision schedules – and on the ISO spine the comparison is one join. This is the verb that turns "I used OWID" into "I used OWID, and here is where it differs from the World Bank".

Usage

compare_sources(
  indicator,
  sources = c("wdi", "owid"),
  year,
  countries = NULL,
  tolerance = 0.05,
  allow_unit_mismatch = FALSE
)

Arguments

indicator

Either one indicator code used for every source, or a named character vector giving each source its own code: c(wdi = "NY.GDP.PCAP.KD", owid = "gdp_per_capita").

sources

Source names to compare (default c("wdi", "owid")).

year

A single year.

countries

Optional iso3c subset.

tolerance

Relative difference above which a country counts as a disagreement (default 0.05, i.e. 5%).

allow_unit_mismatch

Compare anyway when the sources state different units (default FALSE). See below.

Value

A tibble with one row per country: the value from each source, n_sources (how many reported it), rel_diff (max relative spread) and disagrees. The correlation, coverage and disagreement summary is attached as the "countryatlas_source_summary" attribute, with each source's stated unit.

Different units are not a disagreement

GDP per capita in constant 2015 US dollars and in current international dollars differ for every country, and calling that a disagreement between the sources would be wrong. Each fetch records the unit its provider states (see source_info()); when two of them state different units the comparison is refused with class countryatlas_unit_mismatch, naming them. Pass allow_unit_mismatch = TRUE to compare anyway – a ratio that is constant across countries can still be worth seeing – and read rel_diff accordingly. A source that states no unit is not checked.

See also

fetch_indicator(), country_sources()

Examples

if (FALSE) { # \dontrun{
cmp <- compare_sources(c(wdi = "NY.GDP.PCAP.KD", owid = "gdp_per_capita"),
                       sources = c("wdi", "owid"), year = 2020)
attr(cmp, "countryatlas_source_summary")
} # }