Choosing conversion factors

The `source` argument

Use the source argument in convertGDP to control the source of the underlying conversion factors (GDP deflators, MERs and PPPs). This can be one of the sources shipped with the package or a user-defined object.

Package internal ‘sources’

There are two source options shipped with the package, wb_wdi and wb_wdi_linked, with wb_wdi set as the default. Pass the name of a shipped source to the source argument to use it.

library(GDPuc)

my_gdp <- tibble::tibble(
  iso3c = "USA", 
  year = 2010:2014, 
  value = 100:104
)

convertGDP(
  gdp = my_gdp, 
  unit_in = "constant 2010 LCU", 
  unit_out = "constant 2014 Int$PPP",
  source = "wb_wdi_linked",
  verbose = TRUE
)
#> ℹ Converting GDP with conversion factors from wb_wdi_linked:
#> constant 2010 LCU → constant 2014 LCU
#> 2014 value of base 2010 GDP deflator in (constant 2014 LCU per constant 2010
#> LCU) used:
#> USA: 1.07786
#> constant 2014 LCU → constant 2014 Int$PPP
#> 2014 PPP conversion factor in (LCU per international $) used:
#> USA: 1
#> # A tibble: 5 × 3
#>   iso3c  year value
#>   <chr> <int> <dbl>
#> 1 USA    2010  108.
#> 2 USA    2011  109.
#> 3 USA    2012  110.
#> 4 USA    2013  111.
#> 5 USA    2014  112.

Use the function print_source_info to print information on a specific, or all available sources.

print_source_info("wb_wdi")
#> ── wb_wdi ──────────────────────────────────────────────────────────────────────
#> → Origin: The World Bank's World Development Indicator Database
#> → Date: Downloaded on the 30th of April 2024
#> → Html: https://databank.worldbank.org/source/world-development-indicators
#> → Note: Uses the GDP deflator.
#> ────────────────────────────────────────────────────────────────────────────────
print_source_info()
#> ℹ Sources available:
#> ── wb_wdi ──────────────────────────────────────────────────────────────────────
#> → Origin: The World Bank's World Development Indicator Database
#> → Date: Downloaded on the 30th of April 2024
#> → Html: https://databank.worldbank.org/source/world-development-indicators
#> → Note: Uses the GDP deflator.
#> ────────────────────────────────────────────────────────────────────────────────
#> ── wb_wdi_linked ───────────────────────────────────────────────────────────────
#> → Origin: The World Bank's World Development Indicator Database
#> → Date: Downloaded on the 30th of April 2024
#> → Html: https://databank.worldbank.org/source/world-development-indicators
#> → Note: Uses the linked GDP deflator.
#> ────────────────────────────────────────────────────────────────────────────────
#> ── wb_wdi_cpi ──────────────────────────────────────────────────────────────────
#> → Origin: The World Bank's World Development Indicator Database
#> → Date: Downloaded on the 30th of April 2024
#> → Html: https://databank.worldbank.org/source/world-development-indicators
#> → Note: Uses the CPI as deflator.
#> ────────────────────────────────────────────────────────────────────────────────

Use the ::: operator to take a closer look at sources shipped with GDPuc.

GDPuc:::wb_wdi

User-defined ‘source’ objects

Any tibble with columns:

“iso3c” (character),
“year” (numeric),
“GDP deflator” (numeric),
“MER (LCU per US$)” (numeric),
“PPP conversion factor, GDP (LCU per international $)” (numeric)

can be used as a source of conversion factors.

my_custom_source <- tibble::tibble(
  iso3c = "USA", 
  year = 2010:2014, 
  "GDP deflator" = seq(1, 1.1, 0.025),
  "MER (LCU per US$)" = 1,
  "PPP conversion factor, GDP (LCU per international $)" = 1,
)
print(my_custom_source)
#> # A tibble: 5 × 5
#>   iso3c  year `GDP deflator` `MER (LCU per US$)` PPP conversion factor, GDP (L…¹
#>   <chr> <int>          <dbl>               <dbl>                           <dbl>
#> 1 USA    2010           1                      1                               1
#> 2 USA    2011           1.02                   1                               1
#> 3 USA    2012           1.05                   1                               1
#> 4 USA    2013           1.08                   1                               1
#> 5 USA    2014           1.1                    1                               1
#> # ℹ abbreviated name: ¹`PPP conversion factor, GDP (LCU per international $)`

convertGDP(
  gdp = my_gdp, 
  unit_in = "constant 2010 LCU", 
  unit_out = "constant 2014 Int$PPP",
  source = my_custom_source,
  verbose = TRUE
)
#> ℹ Converting GDP with conversion factors from user_provided:
#> constant 2010 LCU → constant 2014 LCU
#> 2014 value of base 2010 GDP deflator in (constant 2014 LCU per constant 2010
#> LCU) used:
#> USA: 1.1
#> constant 2014 LCU → constant 2014 Int$PPP
#> 2014 PPP conversion factor in (LCU per international $) used:
#> USA: 1
#> # A tibble: 5 × 3
#>   iso3c  year value
#>   <chr> <int> <dbl>
#> 1 USA    2010  110 
#> 2 USA    2011  111.
#> 3 USA    2012  112.
#> 4 USA    2013  113.
#> 5 USA    2014  114.

The `use_USA_cf_for_all` argument

In some cases it may be desirable to use the US conversion factors for all countries. For instance, when converting global scenario data from modelling efforts, in US$MER, to another base year. Setting the use_USA_cf_for_all to TRUE ensures that all countries are converted with the US conversion factors.

my_gdp <- tibble::tibble(
  iso3c = c("USA", "IND"), 
  value = 100
)

# Normal conversion, with country specific conversion factors
convertGDP(
  gdp = my_gdp, 
  unit_in = "constant 2005 US$MER", 
  unit_out = "constant 2020 US$MER",
  verbose = TRUE
)
#> ℹ Converting GDP with conversion factors from wb_wdi:
#> constant 2005 US$MER → constant 2005 LCU
#> 2005 MERs in (LCU per US$) used:
#> IND: 44.2736
#> USA: 1
#> constant 2005 LCU → constant 2020 LCU
#> 2020 value of base 2005 GDP deflators in (constant 2020 LCU per constant 2005
#> LCU) used:
#> IND: 2.35925
#> USA: 1.30033
#> constant 2020 LCU → constant 2020 US$MER
#> 2020 MERs in (LCU per US$) used:
#> IND: 74.225
#> USA: 1
#> # A tibble: 2 × 2
#>   iso3c value
#>   <chr> <dbl>
#> 1 USA    130.
#> 2 IND    141.

# Using the US conversion factors for both countries
convertGDP(
  gdp = my_gdp, 
  unit_in = "constant 2005 US$MER", 
  unit_out = "constant 2020 US$MER",
  use_USA_cf_for_all = TRUE,
  verbose = TRUE
)
#> ℹ Converting GDP with conversion factors from wb_wdi:
#> constant 2005 US$MER → constant 2005 LCU
#> 2005 MERs in (LCU per US$) used:
#> IND: 1
#> USA: 1
#> constant 2005 LCU → constant 2020 LCU
#> 2020 value of base 2005 GDP deflators in (constant 2020 LCU per constant 2005
#> LCU) used:
#> IND: 1.30033
#> USA: 1.30033
#> constant 2020 LCU → constant 2020 US$MER
#> 2020 MERs in (LCU per US$) used:
#> IND: 1
#> USA: 1
#> # A tibble: 2 × 2
#>   iso3c value
#>   <chr> <dbl>
#> 1 USA    130.
#> 2 IND    130.

The source argument

Package internal ‘sources’

User-defined ‘source’ objects

The use_USA_cf_for_all argument

The `source` argument

The `use_USA_cf_for_all` argument