| Peterson Institute for International EconomicsEIN 52-1226967 | Research and Public Policy | DC | $14,090,558Large | 92.29 |
| Pioneer InstituteEIN 22-2632081 | Research and Public Policy | MA | $2,124,432Small | 91.51 |
| PolicyLinkEIN 94-3297479 | Research and Public Policy | CA | $12,167,006Mid-sized | 88.22 |
| Population Reference BureauEIN 53-0214030 | Research and Public Policy | DC | $9,157,354Mid-sized | 89.86 |
| Population Research InstituteEIN 54-1819935 | Research and Public Policy | VA | $1,368,353Small | 62.84 |
| Produce for Better Health FoundationEIN 51-0334897 | Research and Public Policy | MO | $2,263,416Small | 86.85 |
| Public AgendaEIN 13-2847587 | Research and Public Policy | NY | $5,183,544Mid-sized | 91.07 |
| Public KnowledgeEIN 52-2336690 | Research and Public Policy | DC | $2,837,102Small | 88.10 |
| RAND CorporationEIN 95-1958142 | Research and Public Policy | CA | $339,414,517Large | 83.79 |
| Reason FoundationEIN 95-3298239 | Research and Public Policy | CA | $12,379,098Mid-sized | 94.64 |
| Research!AmericaEIN 52-1609875 | Research and Public Policy | VA | $3,687,258Mid-sized | 80.61 |
| RESULTS Educational FundEIN 95-3747267 | Research and Public Policy | DC | $12,042,341Mid-sized | 92.82 |
| Robert F. Kennedy Human RightsEIN 13-2522784 | Research and Public Policy | DC | $7,359,062Mid-sized | 83.70 |
| Roper Center for Public Opinion ResearchEIN 51-0173238 | Research and Public Policy | NY | $1,241,433Small | 87.25 |
| Safe Kids WorldwideEIN 52-1627574 | Research and Public Policy | DC | $11,486,479Mid-sized | 89.78 |
| Salzburg Global SeminarEIN 04-2200147 | Research and Public Policy | DC | $8,340,061Mid-sized | 78.57 |
| Securing America's Future EnergyEIN 20-1727977 | Research and Public Policy | DC | $6,080,643Mid-sized | 74.06 |
| Sightline InstituteEIN 52-1833599 | Research and Public Policy | WA | $1,600,591Small | 91.66 |
| Social Venture PartnersEIN 91-1894424 | Research and Public Policy | WA | $2,722,955Small | 83.35 |
| SPUREIN 94-1498232 | Research and Public Policy | CA | $6,462,777Mid-sized | 88.07 |
| State Policy NetworkEIN 57-0952531 | Research and Public Policy | VA | $12,797,260Mid-sized | 88.07 |
| Supportive Housing Network of New YorkEIN 13-3755149 | Research and Public Policy | NY | $1,876,483Small | 87.00 |
| Tanenbaum Center for Interreligious UnderstandingEIN 13-3695475 | Research and Public Policy | NY | $1,992,629Small | 90.41 |
| Tax FoundationEIN 52-1703065 | Research and Public Policy | DC | $4,178,093Mid-sized | 84.96 |
| Texas Health InstituteEIN 74-2237787 | Research and Public Policy | TX | $2,357,814Small | 84.76 |
| Texas Public Policy FoundationEIN 74-2524057 | Research and Public Policy | TX | $8,681,038Mid-sized | 91.89 |
| The Aspen InstituteEIN 84-0399006 | Research and Public Policy | DC | $136,995,834Large | 94.32 |
| The Ayn Rand InstituteEIN 22-2570926 | Research and Public Policy | CA | $9,513,258Mid-sized | 76.96 |
| The Brookings InstitutionEIN 53-0196577 | Research and Public Policy | DC | $100,059,312Large | 83.36 |
| The Center for Democracy and TechnologyEIN 52-1905358 | Research and Public Policy | DC | $5,251,059Mid-sized | 86.38 |
| The Claremont InstituteEIN 95-3443202 | Research and Public Policy | CA | $5,093,063Mid-sized | 83.87 |
| The Council of State GovernmentsEIN 36-6000818 | Research and Public Policy | KY | $39,651,190Large | 80.51 |
| The Family FoundationEIN 52-1425355 | Research and Public Policy | VA | $1,066,485Small | 75.69 |
| The Federalist Society for Law and Public Policy StudiesEIN 36-3235550 | Research and Public Policy | DC | $18,233,577Large | 92.22 |
| The Georgia Center for OpportunityEIN 58-1928520 | Research and Public Policy | GA | $1,640,826Small | 94.69 |
| The Great Plains InstituteEIN 41-1921126 | Research and Public Policy | MN | $5,153,941Mid-sized | 96.97 |
| The Heartland InstituteEIN 36-3309812 | Research and Public Policy | IL | $5,471,048Mid-sized | 86.37 |
| The Heritage FoundationEIN 23-7327730 | Research and Public Policy | DC | $85,427,198Large | 86.19 |
| The Independent InstituteEIN 94-3008370 | Research and Public Policy | CA | $3,196,579Small | 96.38 |
| The Land InstituteEIN 48-0842156 | Research and Public Policy | KS | $3,570,717Mid-sized | 92.36 |
| The Miller Center FoundationEIN 54-1420895 | Research and Public Policy | VA | $2,724,275Small | 74.87 |
| The Naval Institute FoundationEIN 52-1814344 | Research and Public Policy | MD | $8,295,643Mid-sized | 95.11 |
| The Philanthropy RoundtableEIN 13-2943020 | Research and Public Policy | DC | $8,917,853Mid-sized | 91.97 |
| The Safe America FoundationEIN 58-2141636 | Research and Public Policy | GA | $723,271Small | 72.13 |
| Tobin ProjectEIN 20-3105790 | Research and Public Policy | MA | $1,222,784Small | 89.79 |
| Truman Center for National PolicyEIN 52-1080919 | Research and Public Policy | DC | $2,520,516Small | 63.81 |
| U.S., Inc.EIN 38-2418377 | Research and Public Policy | MI | $1,838,596Small | 75.70 |
| United for a Fair EconomyEIN 04-3286118 | Research and Public Policy | MA | $965,479Small | 75.30 |
| United Hospital FundEIN 13-1562656 | Research and Public Policy | NY | $11,358,050Mid-sized | 83.89 |
| United States Hispanic Leadership InstituteEIN 36-3191740 | Research and Public Policy | IL | $1,489,161Small | 81.27 |
| Washington Low Income Housing AllianceEIN 91-1599354 | Research and Public Policy | WA | $1,115,090Small | 76.62 |
| Washington Policy CenterEIN 91-1752769 | Research and Public Policy | WA | $2,233,003Small | 82.76 |
| Women in Government FoundationEIN 54-1527192 | Research and Public Policy | DC | $2,114,054Small | 77.37 |
| Woodrow Wilson International Center for ScholarsEIN 52-1067541 | Research and Public Policy | DC | $23,108,789Large | 90.34 |
| World Environment CenterEIN 13-3100197 | Research and Public Policy | DC | $2,665,851Small | 88.39 |
| World Institute on DisabilityEIN 94-2911623 | Research and Public Policy | CA | $2,330,200Small | 89.50 |