1
$\begingroup$
CountryData["USA", "GDPPerCapita"]

gives $\$45230.20$ per person per year in July, 2015.

But

EntityValue[
  Entity["Country", "UnitedStates"], 
  EntityProperty["Country","GrossDomesticProduct", {"Modifier" -> "PerCapita"}]]

gives $\$55 184.20$ per person per year, closer to other sources but a difference of $22\%$ over the CountryData inquiry.

What is wrong with the CountryData approach?

A problem with The EntityValue approach is that it doesn't work for countries other than the United States. viz:

countries={Entity["Country", "Canada"], Entity["Country", "Cuba"], 
 Entity["Country", "Grenada"], Entity["Country", "Haiti"], 
 Entity["Country", "UnitedStates"]};
In[1]:= EntityValue[#, 
   EntityProperty["Country", 
    "GrossDomesticProduct", {"Modifier" -> 
      "PerCapita"}]] & /@ countries

(* Out: {Missing["NotAvailable"], Missing["NotAvailable"], 
 Missing["NotAvailable"], Missing["NotAvailable"], 
 Quantity[55184.2, ("USDollars")/("People" "Years")]} *)
$\endgroup$
  • 2
    $\begingroup$ You can see some of the sources that CountryData uses here. Beyond this we do not know where that number comes from. If you need this data for something serious, then you should use your own source so you know how old it is and any other limitations. $\endgroup$ – C. E. Jul 26 '15 at 0:29
  • 2
    $\begingroup$ You really should be treating any sort of statistical stuff obtained from the curated data functions as caveat emptor. Better to use a documented source for serious applications, as noted. $\endgroup$ – J. M.'s discontentment Jul 26 '15 at 1:17
  • $\begingroup$ Related: 55653. $\endgroup$ – Sjoerd C. de Vries Jul 26 '15 at 8:38
  • $\begingroup$ Thank you for your comments. In the future I won't trust the curated data, at least for CountryData. What a shame, it could have been very useful, given the ease with which one can access it and manipulate it. $\endgroup$ – Stephen Wilkus Jul 27 '15 at 3:53

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