Add International tax links

_pages/taxes.md

@@ -6,15 +6,15 @@ permalink: /taxes
 nav_order: 24
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-US based nonprofits must file IRS 990 tax forms, even though they may not pay taxes.  [ProPublica's Nonprofit Explorer](https://projects.propublica.org/nonprofits/) makes it simple to report on annual tax-reported income, expenses, and more for US based foundations, giving us a reliable way to compare finances for some organizations.
+US based nonprofits must file IRS 990 tax forms, even though they may not pay taxes.  [ProPublica's Nonprofit Explorer](https://projects.propublica.org/nonprofits/) makes it simple to report on annual tax-reported income, expenses, and more for US based foundations, giving us a reliable way to compare finances for some organizations.  International foundation tax law varies by country, so more research is needed there!
 
-## Basic Tax Data: ProPublica 990 JSONs
+## US Basic Tax Data: ProPublica 990 JSONs
 
 Data is stored per US recognized 501C* nonprofit as a single `ein.json` file in `_data/p990`.  We store this data for convenience, and in case ProPublica's datastore ends.  These 990 JSON data files are generated by ProPublica based on official IRS data dumps of actual processed tax filings.  Data includes IRS-defined metadata about a nonprofit in the `organization` object, and then a list of actual 990 tax filings.  Full details are in [ProPublica's API reference](https://projects.propublica.org/nonprofits/api).
 
 990 filings provide a consistent way to see total revenue, expenses, and assets for any US nonprofit.  They also provide some level of detail within those numbers, in terms of amount of contributions (voluntary donations) versus program expenses or other types of income.
 
-### 990 Data Notes
+### US 990 Data Notes
 
 - **Time Lag** Nonprofits often file taxes late; it also takes a long time for the IRS to publish them, and then ProPublica or other aggregators to parse and quantify them.
 - **Data Errors** I have seen a few figures in ProPublica's rolled-up organization object that were wrong, likely due to scanning or importing errors in their process.
@@ -39,7 +39,14 @@ ProPublica's JSON only shows a subset of 990 filings, and rarely has data bugs (
 - [ ] Automation to update 990s from ProPublica (or wherever) periodically, to find when orgs file new tax years.
 - [ ] Build visualizations of contributions vs. sponsorship model income; especially comparing c3 to c6 orgs.
 
-## Charitable Tax Lookups By Country
+## International Nonprofit Tax Law
+
+Nonprofit taxes vary by country, so Europe is quite complex when comparing different organizations.  While there aren't any completely similar structures in Europe as 501(c)(3)'s, there are some ways to measure equivalent kinds of tax and governance laws.
+
+- [IRS Equivalency Determination](https://www.irs.gov/charities-non-profits/grants-to-foreign-organizations-by-private-foundations) - guidelines for determining if a specific non-US organization is similar enough to a (c)(3)
+- [NGO Source](https://www.ngosource.org/) - an organization specializing in making equivalency determinations
+
+### International Nonprofit Tax Lookup
 
 - EU wide https://e-justice.europa.eu/106/EN/business_registers_in_eu_countries?GERMANY&member=1
 - UK https://register-of-charities.charitycommission.gov.uk/documentation-on-the-api Detailed reports available