用图表说话－咨询人员的基本技能

StepC.SelecttheChartForm(FromComparisontoChart)Eachcomparisonwilllead,inturn,tooneofthefivechartforms.Nowyouhaveseenthat,nomatterwhatyourmessageis,itwillalwaysimplyoneofthefivekindsofcomparison.Itshouldcomeasnosurprisethat,nomatterwhatthecomparisonis,itwillalwaysleadtooneofthefivebasicchartforms:thepiechart,thebarchart,thecolumnchart,thelinechart,andthedotchart.I'veobservedthatthepiechartisthemostpopular.Itshouldn'tbe;it'stheleastpracticalandshouldaccountforlittlemorethan5percentofthechartsusedinapresentationorreport.Ontheotherhand,thebarchartistheleastappreciated.Itshouldreceivemuchmoreattention;it'sthemostversatileandshouldaccountforasmuchas25percentofallchartsused.Iconsiderthecolumncharttobegoodoldreliableandthelinecharttobetheworkhorse;thesetwoshouldaccountforhalfofallchartsused.Whilepossiblyintimidatingatfirstglance,thedotcharthasitsplace10percentofthetime.Thataccountsfor90percent.Theremainderislikelytobethesechartformsusedincombination—say,alinechartwithacolumnchartorapiechartwithabarchart.Let'srecognizethateachchartform,simplyasafunctionofthewayit'sdesigned,isbestequippedtoillustrateoneofthefivecomparisons.Thismatrixillustratestheprimarychoices.Downthesidearethefivebasicchartforms.Acrossthetoparethefivekindsofcomparisonwe'vejustdiscussed.Fortimeseries,frequencydistributions,andcorrelations,youhavetwochoicesofchartforms.Decidingwhichtouseisafunctionoftheamountofdatayou'replotting.Foratimeseriesorfrequencydistribution,usethecolumnchartwhenyouhavefew(say,sixorseven)datapoints;usethelinechartwhenyouhavemany.Foracorrelationcomparison,usethebarcharttoshowfewdata,thedotchartwhenyouhavemany.Let'sworkourwaythroughthematrixandseewhyeachchartformisrecommendedtoshoweachcomparison.Intheprocess,we'lldiscusshowtomakethemostofthechartformsandpresentvariationsforeachthatprovideadditionalinformation.Section1-ChoosingChartsSayItwithCharts:TheExecutive'sGuidetoVisualCommunication,FourthEditionby燝eneZelazny?McGraw-Hill?2001Page1of28SayItwithCharts:TheExecutive'sGuidetoVisualCommunication...22/5/2004=3053&chun...Asweproceed,keepinmindthatchoosing,andespeciallyusing,chartsisnotanexactscience.Andsoyou'llnotealiberalsprinklingofqualifiers,suchas,generally,occasionally,mostofthetime,someofthetime,etc.,allofwhichimplythatyourjudgmentmustplayaroleindecidinghowbesttodesignthecharts.Theoptionspresentedinthematrix,alongwiththesuggestionsformakingthemostofcharts,areguidelines.Moreoftenthannot,however,you'llfindtheseguidelineswillserveyouwell.Beforeturningthepageforaspecificdiscussionofeachcomparisonanditsrecommendedchartform,IsuggestthatyoupauseforawhileandskiptothesecondsectionwhereIpresentaportfolioofallthesechartsatwork.Browsethroughthisshoppinglistofchartstogainanappreciationofhoweffectivechartscanbewhentheyarewellconceivedanddesigned.1.ComponentComparisonAcomponentcomparisoncanbestbedemonstratedusingapiechart.Becauseacirclegivessuchaclearimpressionofbeingatotal,apiechartisideallysuitedfortheone—andonly—purposeitserves:showingthesizeofeachpartasapercentageofsomewhole,suchascompaniesthatmakeupanindustry.ThePieChartPage2of28SayItwithCharts:TheExecutive'sGuidetoVisualCommunication...22/5/2004=3053&chun...Tomakethemostofpiecharts,youshouldgenerallyusenotmorethansixcomponents.Ifyouhavemorethansix,selectthefivecomponentsmostimportanttoyourmessageandgrouptheremainderintoanotherscategory.Becausetheeyeisaccustomedtomeasuringinaclock-wisemotion,positionthemostimportantsegmentagainstthe12o'clocklineand,toaddemphasis,usethemostcontrastingcolor(e.g.,yellowagainstablackbackground),orthemostintenseshadingpatternifproducingthechartinblackandwhite.Ifnoonesegmentismoreimportantthantheothers,considerarrangingthecomponentsfromthelargesttothesmallestorviceversaanduseeitherthesamecolorornoshadingforallsegments.Ingeneral,piechartsaretheleastpracticalofthefivechartforms.Theyarealsothemostmisusedand,worse,themostabused.Forexample,onthenextpageareseveralpseudopiechartsI'vediscoveredovertheyearsinvariouspresentations,newspapers,magazines,andannualreports.NowI'llgrantyoueachisimaginativeandresourceful,evenattractive,althoughexampleDisabitmacabre.Theyarealsoexamplesofformbecomingmoreimportantthancontentand,asaresult,theyfailtopresentaccuratevisualrelationships.Letmestressthattheprimarypurposeofanychartistodemonstraterelationshipsmorequicklyandmoreclearlythanispossibleusingatabularform.Whenevertheformbecomesmoreimportantthanthecontent—thatis,wheneverthedesignofthechartinterfereswithacleargraspoftherelationship—itdoesadisservicetotheaudienceorreaderswhomaybebasingdecisionsonthestrengthofwhattheysee.Let'shavefunanddoanexercisethatteststheusefulnessoftheseexamplesasvisualaids.Togetthemostfromthefollowingworkproject,promisethatyouwillnotthink;recordyourfirstvisualimpression.Foreachexample,startingatthetopandmovingdownoraround,quicklyfillinthepercentageofthetotalcorrespondingtoeachcomponent.Thenaddthetotals.Mostimportant,youCAN'TGOBACK,youCAN'TERASE,