Negative volume index ... Nearly 78 years have passed since Paul L. Dysart, Jr. invented the Negative Volume Index and Positive Volume Index indicators. The ...NegativevolumeindexFromWikipedia,thefreeencyclopediaJumptonavigationJumptosearchNearly78yearshavepassedsincePaulL.Dysart,Jr.inventedtheNegativeVolumeIndexandPositiveVolumeIndexindicators.Theindicatorsremainusefultoidentifyprimarymarkettrendsandreversals.In1936,PaulL.Dysart,Jr.beganaccumulatingtwoseriesofadvancesanddeclinesdistinguishedbywhethervolumewasgreaterorlesserthanthepriorday'svolume.Hecalledthecumulativeseriesforthedayswhenvolumehadbeengreaterthanthepriorday'svolumethePositiveVolumeIndex(PVI),andtheseriesforthedayswhenvolumehadbeenlessertheNegativeVolumeIndex(NVI).AnativeofIowa,DysartworkedinChicago'sLaSalleStreetduringthe1920s.AftergivinguphisChicagoBoardofTrademembership,hepublishedanadvisorylettergearedtoshort-termtradingusingadvance-declinedata.In1933,helaunchedtheTrendwayweeklystockmarketletterandpublishedituntil1969whenhedied.Dysartalsodevelopedthe25-dayPluralityIndex,the25-daytotaloftheabsolutedifferencebetweenthenumberofadvancingissuesandthenumberofdecliningissues,andwasapioneerinusingseveraltypesofvolumeoftradingstudies.RichardRussell,editorofDowTheoryLetters,inhisJanuary7,1976lettercalledDysart"oneofthemostbrilliantofthepioneermarkettechnicians."Contents1Dysart’sNVIandPVI2Dysart’sInterpretationofNVIandPVI3Fosback’sVariations4ReferencesDysart’sNVIandPVI[edit]ThedailyvolumeoftheNewYorkStockExchangeandtheNYSECompositeIndex'sadvancesanddeclinesdroveDysart'sindicators.Dysartbelievedthat“volumeisthedrivingforceinthemarket.”Hebeganstudyingmarketbreadthnumbersin1931,andwasfamiliarwiththeworkofLeonardP.AyresandJamesF.Hughes,whopioneeredthetabulationofadvancesanddeclinestointerpretstockmarketmovements.DysartcalculatedNVIasfollows:1)iftoday'svolumeislessthanyesterday'svolume,subtractdeclinesfromadvances,2)addthedifferencetothecumulativeNVIbeginningatzero,and3)retainthecurrentNVIreadingforthedayswhenvol