The doctrines Illinois courts name when they cite: mined from the sentence each citation lives in, keyed on the citing court, counted by distinct opinions. Entry by issue, not by case: pick one to see the cases on each side.
| # | Issue | Most-cited case | Opinions | Courts | Years | Last 5y |
|---|---|---|---|---|---|---|
| 1 | plain error | People v. Piatkowski | 5,007 | 2 | 1872–2026 | 1,551 |
| 2 | affirmative defense | Greer v. Illinois Housing Development Authority | 3,182 | 3 | 1893–2026 | 625 |
| 3 | due process clause | In Re WINSHIP | 2,693 | 3 | 1923–2026 | 418 |
| 4 | de novo standard | People v. Vincent | 2,388 | 2 | 1962–2026 | 530 |
| 5 | abuse of discretion standard | People v. Wheeler | 2,286 | 2 | 1898–2026 | 639 |
| 6 | Strickland test | Strickland v. Washington | 2,140 | 2 | 1978–2026 | 862 |
| 7 | clear or obvious error | People v. Piatkowski | 1,767 | 2 | 2007–2026 | 950 |
| 8 | fundamental rule | Michigan Avenue National Bank v. County of Cook | 1,588 | 3 | 1871–2026 | 183 |
| 9 | hearsay rule | The People v. Poland | 1,581 | 2 | 1922–2026 | 223 |
| 10 | seriousness error | People v. Piatkowski | 1,547 | 2 | 1963–2026 | 692 |
| 11 | Miranda warning | Miranda v. Arizona | 1,358 | 2 | 1968–2026 | 204 |
| 12 | res judicata doctrine | Rein v. David A. Noyes & Co. | 1,046 | 3 | 1888–2026 | 224 |
| 13 | proportionate penalties clause | People v. Miller | 994 | 2 | 1992–2026 | 494 |
| 14 | ineffective assistance claim | Strickland v. Washington | 931 | 2 | 1985–2026 | 428 |
| 15 | equal protection clause | Batson v. Kentucky | 902 | 2 | 1918–2026 | 72 |
| 16 | ineffective assistance of counsel claim | Strickland v. Washington | 891 | 2 | 1985–2026 | 368 |
| 17 | exclusionary rule | United States v. Leon | 785 | 2 | 1956–2026 | 99 |
| 18 | Terry stop | Terry v. Ohio | 747 | 2 | 1977–2026 | 106 |
| 19 | public interest exception | In Re Alfred HH | 724 | 2 | 1970–2026 | 148 |
| 20 | gist of a constitutional claim | People v. Gaultney | 718 | 2 | 1992–2026 | 316 |
| 21 | confrontation clause | Crawford v. Washington | 709 | 2 | 1969–2026 | 113 |
| 22 | forfeiture rule | People v. Thompson | 690 | 2 | 1891–2026 | 263 |
| 23 | harmless error | People v. Thurow | 690 | 2 | 1891–2026 | 145 |
| 24 | reasonable doubt standard | People v. Patterson | 678 | 2 | 1905–2026 | 115 |
| 25 | cause-and-prejudice test | People v. Pitsonbarger | 664 | 2 | 1999–2026 | 346 |
| 26 | Krankel inquiry | People v. Krankel | 656 | 2 | 1993–2026 | 383 |
| 27 | fitness hearing | People v. Brandon | 646 | 2 | 1975–2026 | 158 |
| 28 | mootness doctrine | In Re Alfred HH | 646 | 2 | 1965–2026 | 127 |
| 29 | per se rule | The People v. Stoval | 638 | 2 | 1974–2026 | 62 |
| 30 | rational basis test | People v. Adams | 630 | 2 | 1980–2026 | 54 |
| 31 | third-stage evidentiary hearing | People v. Domagala | 622 | 2 | 2001–2026 | 398 |
| 32 | double jeopardy clause | People v. Olivera | 593 | 2 | 1958–2026 | 83 |
| 33 | manifest weight standard | Best v. Best | 568 | 2 | 1960–2026 | 258 |
| 34 | warrant requirement | Terry v. Ohio | 561 | 2 | 1970–2026 | 104 |
| 35 | forfeited error | People v. Herron | 539 | 2 | 1994–2026 | 211 |
| 36 | existence of a meritorious defense | Smith v. Airoom, Inc. | 479 | 2 | 1967–2026 | 108 |
| 37 | IPI instruction | People v. Pollock | 410 | 2 | 1964–2026 | 49 |
| 38 | probable cause hearing | Terry v. Ohio | 408 | 2 | 1966–2026 | 63 |
| 39 | law of the case doctrine | People v. Tenner | 388 | 2 | 1939–2026 | 79 |
| 40 | home rule | Palm v. 2800 Lake Shore Drive Condominium Assn'n | 383 | 2 | 1972–2026 | 43 |
| 41 | manifest-weight-of-the-evidence standard | People v. Trottier | 377 | 2 | 1986–2026 | 194 |
| 42 | invited error | People v. Carter | 374 | 2 | 1992–2026 | 201 |
| 43 | Fifth Amendment privilege | Miranda v. Arizona | 369 | 2 | 1959–2026 | 30 |
| 44 | Illinois rule | People v. Harris | 367 | 3 | 1906–2026 | 30 |
| 45 | innocence claim | People v. Robinson | 356 | 2 | 2004–2026 | 256 |
| 46 | issue under the plain error | People v. Piatkowski | 350 | 2 | 1974–2026 | 73 |
| 47 | Miller factors | People v. Holman | 345 | 3 | 1974–2026 | 205 |
| 48 | separation of powers doctrine | Best v. Taylor MacHine Works | 344 | 2 | 1958–2026 | 31 |
| 49 | burden of rebutting presumption | Russell v. Department of Natural Resources | 341 | 2 | 1851–2026 | 48 |
| 50 | Fourth Amendment violation | People v. Henderson | 338 | 2 | 1971–2026 | 61 |
| 51 | fair sentencing hearing | People v. Hillier | 321 | 2 | 1978–2026 | 95 |
| 52 | attorney-client privilege | Waste Management, Inc. v. International Surplus Lines Insurance | 319 | 2 | 1956–2026 | 33 |
| 53 | Batson hearing | Batson v. Kentucky | 316 | 2 | 1986–2026 | 40 |
| 54 | evidence at the sentencing hearing | People v. Hillier | 316 | 2 | 1984–2026 | 202 |
| 55 | manifest error | People v. Morgan | 309 | 2 | 1886–2026 | 186 |
| 56 | Frye hearing | Frye v. United States | 308 | 2 | 1983–2026 | 36 |
| 57 | good faith exception | United States v. Leon | 307 | 2 | 1899–2026 | 46 |
| 58 | clear and obvious error | People v. Piatkowski | 305 | 2 | 2007–2026 | 159 |
| 59 | Brady violation | Brady v. Maryland | 303 | 2 | 1972–2026 | 116 |
| 60 | insanity defense | People v. Stack | 295 | 2 | 1965–2026 | 41 |
| 61 | sovereign immunity | Molitor v. Kaneland Community Unit District No. 302 | 290 | 3 | 1953–2025 | 29 |
| 62 | estoppel doctrine | Employers Insurance v. Ehlco Liquidating Trust | 282 | 3 | 1877–2025 | 15 |
| 63 | collateral estoppel doctrine | Ashe v. Swenson | 277 | 2 | 1971–2026 | 29 |
| 64 | self-defense instruction | People v. Lockett | 275 | 2 | 1913–2026 | 91 |
| 65 | showing violation | People v. Coleman | 275 | 2 | 1900–2026 | 70 |
| 66 | alibi defense | People v. Krankel | 273 | 2 | 1934–2026 | 57 |
| 67 | defendant a fair sentencing hearing | People v. Hillier | 272 | 2 | 1985–2026 | 184 |
| 68 | knowing and intelligent waiver | Miranda v. Arizona | 272 | 2 | 1971–2026 | 56 |
| 69 | pro se posttrial claim | People v. Moore | 268 | 2 | 2003–2026 | 126 |
| 70 | structural error | People v. Thompson | 265 | 2 | 1974–2026 | 106 |
| 71 | Apprendi violation | People v. Thurow | 262 | 2 | 2000–2025 | 34 |
| 72 | forum non conveniens doctrine | Dawdy v. Union Pacific RR Co. | 259 | 2 | 1948–2026 | 42 |
| 73 | Pedrick standard | Pedrick v. Peoria & Eastern Railroad | 247 | 2 | 1968–2025 | 6 |
| 74 | respondeat superior doctrine | Towns v. Yellow Cab Co. | 245 | 3 | 1866–2025 | 13 |
| 75 | pro se claim | People v. Moore | 244 | 2 | 1990–2026 | 132 |
| 76 | capital sentencing hearing | Strickland v. Washington | 242 | 2 | 1983–2024 | 1 |
| 77 | lesser included offense instruction | People v. Medina | 242 | 2 | 1978–2026 | 50 |
| 78 | standing requirement | In Re Custody of Peterson | 242 | 2 | 1869–2026 | 42 |
| 79 | best-interests hearing | In Re DT | 234 | 2 | 1981–2026 | 148 |
| 80 | tendered instruction | Linn v. Damilano | 233 | 2 | 1944–2026 | 11 |
| 81 | resulting conviction bar | People v. Pujoue | 232 | 2 | 1975–2026 | 28 |
| 82 | as-applied constitutional challenge | People v. Thompson | 223 | 2 | 2015–2026 | 146 |
| 83 | non-IPI instruction | People v. Pollock | 222 | 2 | 1975–2026 | 30 |
| 84 | factual basis claim | People v. Moore | 218 | 2 | 1969–2026 | 90 |
| 85 | facts satisfy the statutory standard | AFM Messenger Service, Inc. v. Department of Employment Security | 217 | 2 | 2000–2026 | 51 |
| 86 | second prong of plain error | People v. Thompson | 216 | 2 | 2007–2026 | 78 |
| 87 | claim of sentencing error | People v. Hillier | 214 | 2 | 2010–2026 | 148 |
| 88 | speedy trial violation | People v. Phipps | 210 | 2 | 1971–2026 | 69 |
| 89 | detention hearing | People v. Morgan | 209 | 2 | 1968–2026 | 173 |
| 90 | res judicata provides that a final doctrine | Rein v. David A. Noyes & Co. | 206 | 2 | 1976–2026 | 39 |
| 91 | qualified privilege | Kuwik v. Starmark Star Marketing & Administration, Inc. | 203 | 3 | 1944–2026 | 20 |
| 92 | personal claim | Underground Contractors Ass'n v. City of Chicago | 202 | 2 | 1880–2026 | 18 |
| 93 | second prong test | Strickland v. Washington | 201 | 2 | 1979–2026 | 53 |
| 94 | guilty plea hearing | People v. Stroud | 200 | 2 | 1975–2026 | 65 |
| 95 | arguable claim | People v. Hodges | 199 | 2 | 2010–2026 | 127 |
| 96 | legal malpractice claim | Northern Illinois Emergency Physicians v. Landau, Omahana & Kopka, Ltd. | 199 | 2 | 1980–2026 | 43 |
| 97 | private interest factors | First Nat. Bank v. Guerine | 196 | 2 | 1984–2026 | 42 |
| 98 | laches doctrine | Pyle v. Ferrell | 193 | 2 | 1882–2026 | 25 |
| 99 | exhaustion doctrine | Castaneda v. Illinois Human Rights Commission | 189 | 3 | 1963–2026 | 27 |
| 100 | sufficiency of the evidence claim | Jackson v. Virginia | 189 | 2 | 1989–2026 | 67 |
| 101 | equitable estoppel doctrine | Patrick Engineering, Inc. v. The City of Naperville | 183 | 2 | 1885–2026 | 13 |
| 102 | prima facie presumption | Duren v. Missouri | 180 | 2 | 1892–2026 | 31 |
| 103 | totality of the circumstances analysis | Illinois v. Gates | 179 | 2 | 1974–2026 | 31 |
| 104 | statute of limitations defense | Mittelman v. Witous | 177 | 2 | 1887–2025 | 16 |
| 105 | death penalty hearing | People v. Davis | 176 | 2 | 1979–2026 | 4 |
| 106 | stare decisis doctrine | Cates v. Cates | 175 | 2 | 1914–2026 | 16 |
| 107 | party cannot complain error | In Re Detention of Swope | 174 | 2 | 1911–2026 | 71 |
| 108 | prejudicial error | Gillespie v. Chrysler Motors Corp. | 173 | 2 | 1899–2026 | 21 |
| 109 | res ipsa loquitur doctrine | Metz v. Central Illinois Electric & Gas Co. | 173 | 3 | 1900–2025 | 6 |
| 110 | clear and convincing standard | In Re DT | 171 | 2 | 1975–2026 | 25 |
| 111 | deviation standard | Purtill v. Hess | 171 | 3 | 1964–2026 | 18 |
| 112 | Montgomery rule | The People v. Montgomery | 171 | 2 | 1973–2025 | 23 |
| 113 | contribution claim | Laue v. Leifheit | 169 | 3 | 1969–2026 | 17 |
| 114 | gist claim | People v. Dredge | 169 | 2 | 1920–2026 | 58 |
| 115 | innocent construction rule | Chapski v. Copley Press | 168 | 3 | 1960–2026 | 8 |
| 116 | preponderance of the evidence standard | Best v. Best | 168 | 2 | 1967–2026 | 28 |
| 117 | proximate cause instruction | Leonardi v. Loyola University of Chicago | 168 | 2 | 1911–2026 | 29 |
| 118 | noted rule | People v. Hanson | 165 | 2 | 1935–2026 | 11 |
| 119 | transactional test | River Park, Inc. v. City of Highland Park | 165 | 2 | 1980–2026 | 28 |
| 120 | penalty violation | City of Chicago v. Knobel | 160 | 2 | 1873–2026 | 6 |
| 121 | policy defense | Kenilworth Insurance v. McDougal | 160 | 3 | 1895–2026 | 7 |
| 122 | vagueness challenge | People v. Greco | 160 | 2 | 1980–2026 | 16 |
| 123 | involuntary manslaughter instruction | People v. DiVincenzo | 159 | 2 | 1975–2026 | 12 |
| 124 | concluded error | People v. Hernandez | 158 | 2 | 1908–2026 | 18 |
| 125 | first step analysis | People v. Piatkowski | 156 | 2 | 1981–2026 | 61 |
| 126 | determines claim | People v. Moore | 153 | 2 | 1989–2026 | 73 |
| 127 | knowing waiver | In Re RAB | 153 | 2 | 1966–2026 | 18 |
| 128 | parol evidence rule | Eichengreen v. Rollins, Inc. | 153 | 2 | 1877–2025 | 6 |
| 129 | difficult challenge | Napleton v. Village of Hinsdale | 151 | 2 | 1994–2026 | 55 |
| 130 | failure to raise claim | People v. Edwards | 151 | 2 | 1976–2026 | 75 |
| 131 | plain language rule | DeSMET EX REL. v. County of Rock Island | 149 | 2 | 1893–2026 | 42 |
| 132 | pretrial detention hearing | People v. Morgan | 149 | 2 | 1995–2026 | 148 |
| 133 | probation revocation hearing | People v. Grayson | 149 | 2 | 1969–2026 | 15 |
| 134 | third-stage hearing | People v. Coleman | 149 | 2 | 1995–2026 | 101 |
| 135 | felony-murder rule | People v. Lowery | 148 | 2 | 1965–2025 | 9 |
| 136 | plain view doctrine | Coolidge v. New Hampshire | 148 | 2 | 1968–2025 | 30 |
| 137 | supremacy clause | Carter v. SSC Odin Operating Co., LLC | 147 | 2 | 1953–2026 | 20 |
| 138 | defective reasonable doubt instruction | People v. Thompson | 146 | 2 | 2009–2026 | 62 |
| 139 | Jackson standard | People v. Cunningham | 146 | 2 | 1969–2026 | 34 |
| 140 | pattern instruction | Schultz v. NORTHEAST ILL. REGIONAL COMMUTER RAILROAD CORP. | 146 | 2 | 1973–2026 | 21 |
| 141 | uniformity clause | Geja's Cafe v. Metropolitan Pier & Exposition Authority | 145 | 2 | 1908–2026 | 6 |
| 142 | pleading requirement | McCastle v. Sheinkop | 144 | 2 | 1878–2026 | 43 |
| 143 | elementary rule | Smithberg v. Illinois Municipal Retirement Fund | 143 | 3 | 1873–2026 | 15 |
| 144 | appeal or writ error | The People v. Redlich | 142 | 2 | 1843–2018 | 0 |
| 145 | issue for plain error | People v. Ramsey | 142 | 2 | 1983–2026 | 69 |
| 146 | presence of mitigating factors | People v. Quintana | 142 | 2 | 1987–2026 | 88 |
| 147 | second degree murder instruction | People v. Lockett | 142 | 2 | 1990–2026 | 26 |
| 148 | first step in plain error | People v. Piatkowski | 141 | 2 | 2010–2026 | 86 |
| 149 | conducted hearing | People v. Krankel | 140 | 2 | 1956–2026 | 40 |
| 150 | open and obvious doctrine | Ward v. K Mart Corp. | 140 | 2 | 1991–2026 | 28 |
Top 150 by distinct citing opinions.