mayo foundation medical education research et al argued november decided january petitioners hereinafter mayo offer residency programs doctors graduated medical school seek additional instruction chosen specialty programs train doctors primarily experience although residents required take part formal educational activities doctors generally spend bulk time typically hours week caring patients mayo pays residents annual stipends also provides health insurance malpractice insurance paid vacation time federal insurance contributions act fica requires employees employers pay taxes wages employees receive defines wages include remuneration employment fica defines employment service performed employee person employing excludes taxation service performed employ school college university service performed student enrolled regularly attending classes school since treasury department construed student exception exempt taxation students work schools incident purpose pursuing course study fed reg department issued regulations providing services employee includes employee normally scheduled work hours per week incident purpose pursuing course study cfr iii department explained analysis affected fact services may educational instructional training aspect ibid rule offers example medical resident whose normal schedule requires perform services hours per week concludes resident student mayo filed suit asserting rule invalid district agreed found employee rule inconsistent unambiguous text concluded factors governing analysis national muffler dealers also indicated rule invalid eighth circuit reversed applying chevron natural resources defense council appeals concluded department regulation permissible interpretation ambiguous statute held treasury department employee rule reasonable construction pp chevron framework first asks whether congress directly addressed precise question issue congress done statute define student otherwise attend question whether medical residents subject fica pp parties debate whether next apply chevron step two analysis used review tax regulation national muffler absent justification inclined apply less deferential framework evaluate treasury department regulations uses review rules adopted agency ecogniz ed importance maintaining uniform approach judicial review administrative action dickinson zurko principles underlying chevron apply full force tax context chevron recognized agency power administer congressionally created program necessarily requires formulation policy making rules fill gap left congress filling gaps internal revenue code plainly requires treasury department make interpretive choices statutory implementation least complex ones made agencies administering statutes true employee rule like rule issue national muffler promulgated department general authority prescribe needful rules regulations enforcement internal revenue code also true opinions predating chevron stated owed less deference rule adopted general grant authority afford rules issued pursuant specific grants see rowan vogel fertilizer since however found chevron deference appropriate appears congress delegated authority agency generally make rules carrying force law agency interpretation claiming deference promulgated exercise authority mead chevron mead provide appropriate framework evaluating employee rule department issued rule pursuant explicit authorization prescribe needful rules regulations procedures recognized good indicators rule meriting chevron deference mead pp rule easily satisfies chevron second step mayo accepts treasury department determination individual may qualify student exception unless educational aspect relationship employer predominates service aspect relationship objects department conclusion residents working hours per week categorically satisfy requirement mayo argues treasury department required engage inquiry employee department arbitrarily distinguished training classroom instruction regulation like legislation often requires drawing lines department reasonably sought distinguish workers study students work focusing hours spent working spent studies sensible way accomplish goal department thus drawn distinction education service classroom instruction training treasury department also reasonably concluded employee rule improve administrability fed reg thereby avoided wasteful litigation continuing uncertainty inevitably accompany approach like one mayo advocates correll moreover rule reasonably takes account social security administration concern exempting residents fica deprive families vital social security disability survivorship benefits pp affirmed roberts delivered opinion members joined except kagan took part consideration decision case mayo foundation medical education research et petitioners writ certiorari appeals eighth circuit january chief justice roberts delivered opinion nearly americans work wages pay taxes wages federal insurance contributions act fica congress enacted collect funds social security question presented case whether doctors serve medical residents properly viewed student whose service congress exempted fica taxes doctors graduate medical school pursue additional education specialty become board certified practice field petitioners mayo foundation medical education research mayo clinic regents university minnesota collectively mayo offer medical residency programs provide instruction mayo residency programs usually last three five years train doctors primarily experience residents often spend hours week caring patients typically examining diagnosing prescribing medication recommending plans care performing certain procedures residents generally supervised work senior residents faculty members known attending physicians mayo paid residents annual stipends ranging provided health insurance malpractice insurance paid vacation time mayo residents also take part formal structured educational program brief petitioners internal quotation marks omitted residents assigned textbooks journal articles read expected attend weekly lectures conferences residents also take written exams evaluated attending faculty physicians parties dispute bulk residents time spent caring patients social security act related legislation congress created comprehensive national insurance system provides benefits retired workers disabled workers unemployed workers families see lee nn congress funds social security taxing employers employees fica wages employees earn see tax employees tax employers congress defined wages broadly encompass remuneration employment ed supp iii term employment similarly broad reach extending service whatever nature performed employee person employing congress however exempted certain categories service individuals fica demands relevant congress excluded taxation service performed employ school college university service performed student enrolled regularly attending classes school college university social security act governs workers eligibility benefits contains corresponding student exception materially identical since treasury department applied student exception exempt taxation students work schools incident purpose pursuing course study fed reg adopting treas regs see treas reg cfr department determined whether individual work incident studies performing analysis primary considerations analysis number hours worked course load taken see rev rul cum bull services individual employed basis course load incident purpose pursuing course study part social security administration ssa also articulated regulations approach corresponding student exception social security act see cfr ssa however always held resident physicians students ssr cum bull appeals eighth circuit held ssa categorically exclude residents student status given regulations provided approach see minnesota apfel following decision internal revenue service received claims seeking fica tax refunds ground medical residents qualified students internal revenue code facing flood claims treasury department determined wa necessary provide additional clarification ter student used particularly respect individuals perform services nature job training fed reg department proposed amended rule comment held public hearing see december department adopted amended rule prescribing employee service incident studies educational aspect relationship employer employee compared service aspect relationship predominant treas reg cfr rule categorically provides services employee defined employer policies event including employee normally scheduled work hours per week incident purpose pursuing course study fed reg treas reg iii cfr iii employee rule amended provision clarifies department analysis affected fact services performed may educational instructional training aspect ibid rule also includes example case employee employed university medical resident fed reg treas reg cfr example employee normal work schedule calls perform services hours per week rule provides service incident purpose pursuing course study accordingly exempt student fed reg treas reg cfr example department promulgated employee rule mayo filed suit seeking refund money withheld paid residents stipends second quarter supp regents univ apr app pet cert mayo asserted residents exempt treasury department employee rule invalid district granted mayo motion summary judgment held employee rule inconsistent unambiguous text understood dictate employee long educational aspect service predominates service aspect relationship employer supp also determined factors governing analysis regulations set forth national muffler dealers indicate employee exception invalid supp see app pet cert government appealed appeals reversed applying opinion chevron natural resources defense council appeals concluded statute silent ambiguous question whether medical resident working school purposes department amended regulation permissible interpretation statut granted mayo petition certiorari ii begin analysis first step framework announced chevron supra ask whether congress directly addressed precise question issue agree appeals congress done statute define term student otherwise attend precise question whether medical residents subject fica see mayo nonetheless contends treasury department employee rule must rejected chevron step one mayo argues dictionary definition student one engages applying mind acquisition learning whether means books observation plainly encompasses residents brief petitioners quoting oxford universal dictionary ed mayo adds residents excluded category limitation students congress imposed statute regularly attending classes school brief petitioners quoting mayo reading eliminate statute ambiguity applied working professionals reply brief mayo acknowledges professor taking evening classes person presumably satisfy statute requirement apply mind learning excluded exemption taxed ly student reply brief petitioners medical residents might likewise excluded basis statute resolve ambiguity district interpreted unambiguously foreclosing department rule mandating employee deemed long educational aspect service predominates service aspect relationship employer supp think possible glean much little provides event statutory text still offer insight congress intended predominance determined whether congress thought medical residents satisfy requirement extent congress specifically addressed medical residents moreover expressly excluded doctors exemptions might otherwise invoke see ii excluding medical residents exemptions available employees district columbia choice casts doubt claim congress specifically intended insulate medical residents fica reach first place sum neither plain text statute district interpretation exemption speak precision necessary say definitively whether statute applies medical residents eurodif slip typical case ambiguity lead us inexorably chevron step two may disturb agency rule unless capricious substance manifestly contrary statute household credit services pfennig quoting mead case however parties disagree proper framework evaluating ambiguous provision internal revenue code mayo asks us apply analysis used review tax regulation national muffler explained regulation may particular force substantially contemporaneous construction statute presumed aware congressional intent regulation dates later period manner evolved merits inquiry relevant considerations length time regulation effect reliance placed consistency commissioner interpretation degree scrutiny congress devoted regulation subsequent statute government hand contends national muffler standard superseded chevron sole question step two chevron analysis whether agency answer based permissible construction statute since deciding chevron cited national muffler chevron review treasury department regulations see cleveland indians baseball citing national muffler cottage savings assn commissioner boyle citing chevron see also atlantic mut ins commissioner citing chevron cottage savings although thus far distinguished national muffler chevron call different analyses ambiguous statute national muffler example might view agency interpretation statute heightened skepticism consistent time promulgated years relevant statute enacted way regulation evolved district case cited factors rejecting treasury department rule noting particular regulation promulgated adverse judicial decision see supp see also brief petitioners relying considerations chevron contrast deference agency interpretation ambiguous statute turn considerations repeatedly held gency inconsistency basis declining analyze agency interpretation chevron framework national cable telecommunications assn brand internet services accord eurodif supra slip instructed neither antiquity contemporaneity statute condition regulation validity smiley citibank south dakota found immaterial analysis regulation prompted litigation indeed dominion industries expressly invited treasury department amend regulations troubled consequences resolution case aside past citation national muffler mayo advanced justification applying less deferential standard review treasury department regulations apply rules agency absence justification inclined carve approach administrative review good tax law contrary expressly ecogniz ed importance maintaining uniform approach judicial review administrative action dickinson zurko see skinner pipeline declining apply different stricter nondelegation doctrine cases congress delegates discretionary authority executive taxing power principles underlying decision chevron apply full force tax context chevron recognized power administrative agency administer congressionally created program necessarily requires formulation policy making rules fill gap left implicitly explicitly congress internal quotation marks omitted acknowledged formulation policy might require ordinary knowledge respecting matters subjected agency regulations internal quotation marks omitted filling gaps internal revenue code plainly requires treasury department make interpretive choices statutory implementation least complex ones agencies must make administering statutes cf bob jones univ area complex tax system agency congress vests administrative responsibility must able exercise authority meet changing conditions new problems see reason review tax regulations guided agency expertise pursuant chevron extent review regulations one mayo amici points however employee rule rule issue national muffler promulgated pursuant treasury department general authority prescribe needful rules regulations enforcement internal revenue code see brief carlton smith two decisions predating chevron stated owe treasury department interpretation less deference contained rule adopted general authority issued specific grant authority define statutory term prescribe method executing statutory provision rowan vogel fertilizer quoting rowan since rowan vogel decided however administrative landscape changed significantly held chevron deference appropriate appears congress delegated authority agency generally make rules carrying force law agency interpretation claiming deference promulgated exercise authority mead inquiry regard turn whether congress delegation authority general specific example national cable telecommunications supra held federal communications commission delegated authority promulgate binding legal rules entitled chevron deference statutes gave commission authority enforce rules regulations may necessary public interest carry provisions communications act quoting see also sullivan everhart applying chevron deference rule promulgated pursuant delegation general authority rules regulations establish procedures inconsistent provisions subchapter necessary appropriate carry quoting believe chevron mead rather national muffler rowan provide appropriate framework evaluating employee rule department issued employee rule pursuant explicit authorization prescribe needful rules regulations enforcement internal revenue code found express congressional authorizations engage process rulemaking good indicator delegation meriting chevron treatment mead supra department issued employee rule procedures fed reg consideration identified precedents significant sign rule merits chevron deference mead supra see long island care home coke explained ultimate question whether congress intended expected courts treat regulation within outside delegation agency authority emphasis deleted long island care case found chevron provided appropriate standard review agency rule sets forth important individual rights duties agency focuses fully directly upon issue agency uses full procedures promulgate rule resulting rule falls within statutory grant authority considerations point result case falls squarely within bounds properly analyzed chevron mead employee rule easily satisfies second step chevron asks whether department rule reasonable interpretation enacted text begin mayo accepts aspect relationship employer employee compared service aspect relationship must order individual qualify exemption reply brief petitioners quoting treas reg cfr mayo objects however department conclusion residents work hours per week categorically satisfy requirement residents employment educational mayo argues hours resident spends working make student less one reply brief petitioners emphasis deleted mayo contends treasury department required engage inquiry employee service mayo also objects department drawn arbitrary distinction training classroom instruction brief petitioners disagree regulation like legislation often requires drawing lines mayo dispute treasury department reasonably sought way distinguish workers study students work see irs letter ruling may focusing hours individual works hours spends studies perfectly sensible way accomplishing goal department explained individual service course study separate distinct activities vast majority cases reasoned mployees working enough hours considered employees filled conventional measure available time work study fed reg department thus distinguish classroom education clinical training rather education service department reasonably concluded employee rule improve administrability thereby avoided wasteful litigation continuing uncertainty inevitably accompany purely approach like one mayo advocates correll treasury department explained moreover employee rule recommend administrative convenience department reasonably determined taxing residents fica purpose social security act comport precedent treasury department appreciated understood terms social security act breadth coverage fed reg quoting social security bd nierotko instructed exemptions taxation construed narrowly bingler johnson although mayo contends medical residents yet begun working lives fully trained reply brief petitioners internal quotation marks omitted department certainly act irrationally concluding doctors work long hours serve highly skilled professionals typically share terms employment career employees kind workers congress intended contribute benefit social security system fed reg department rule takes account ssa concern exempting residents fica deprive residents families vital disability survivorship benefits social security provides mayo wonders whether employee rule result residents taxed fica denied coverage ssa government informs us however ssa continues adhere longstanding position medical residents students thus remain eligible coverage brief tr oral arg doubt mayo residents engaged valuable educational pursuit students craft question whether students purposes however different matter one congress directly spoken treasury department rule reasonable construction congress said judgment appeals must affirmed ordered justice kagan took part consideration decision case