The tiger that isn't: seeing through a world of numbers PDF
Preview The tiger that isn't: seeing through a world of numbers
'EveryjournalistshouldgetpaidleavetoreadandrereadTheTigerThatIsn'tuntilthey'veunderstoodhowtheyare being spun' –New Scientist 'Personal and practical … might even cause a social revolution' –Independent 'Thisveryelegantbookconstantlysparks“Aha!”momentsasitinterrogatesthewaynumbersarehandledandmis- handled by politicians and the media' – Steven Poole,Guardian 'Averyfunnybook…thisisoneofthosemathsbooksthatclaimstobeself-help,andontheevidencepresentedhere, we are in dire need of it' –Daily Telegraph 'This delightful book should be compulsory reading for everyone responsible for presenting data and for everyone who consumes it' –Sunday Telegraph 'Clear-eyed and concise' –The Times 'Abookaboutnumbersandhowtointerpretthemdoesn'tsoundlikeinterestingbedtimereading.Yetinthehandsof MichaelBlastlandandAndrewDilnot,thatiswhatitbecomes…areliableguidetoatreacheroussubject,givingits readersthementalammunitiontomakesenseofofficialclaims.Thatitmanagestomakethemlaughatthesametime is a rare and welcome feat' –Economist 'IhavesatwithAndrewDilnotinmanytelevisionstudiosandwatchedwithaweasheevisceratespoliticianswhoare tryingtodistortthefigurestosuitthemselves.Heisruthlessinexposingtheliesthatstatisticscanseemtosupport. Thiswittyandfascinatingbookexplainstouslaymenhowtomakesenseofnumbersandhowwecanavoidhaving the wool pulled over our eyes. Invaluable' – David Dimbleby 'A very fine book' – Rod Liddle,Spectator 'Withanappealingcombinationofdrywitandnumeratecommonsense,theauthorssucceedinseeingoffmany“ti- gers”' –Financial Times 'Aneye-opening lightning tourthroughthedaily useandabuseof“killer facts”: thewaythat statistics canbeguile, distortandmislead…Thisisessentialreadingforanyoneinterestedinpolitics,economicsorcurrentaffairs'–Scot- landon Sunday 'Brilliantexcursionintothewaywemisuseandmisunderstandnumbersandstatistics,andhowtoseearoundit…A greatexperience.Veryreadable,alwaysinformativeandoftenentertaining,thisisabookthateverypolitician,civil servant and, well, everyone should read' –popularscience.co.uk 'A book that is both illuminating and highly entertaining' – Geoff Barton,Times Educational Supplement 'Theargumentsarefascinatingandtheexamplesaccessibleandrelevant.Notonlyformathematicians,butforevery- onewhoreadsthenewspaperorwatchesthenews.Journalistswouldbeadvisedtoreaditcloselyandmathsorstats teachers will find a wealth of real-life examples for direct use in the classroom' –Plus,online maths magazine 'The Tiger That Isn't is that rarest of things: a compelling book about statistics. The book does a superb job at re- minding us that numbers can only go so far in describing our very messy, very complicated, very human world' – readysteadybook.com 'Thisbookisavaliantattempttoencouragehealthyscepticismaboutstatistics,againstacultureinwhichbothnews producers and consumers like extreme possibilities more than likely ones' –New Statesman 'How to use the knowledge we already possess to understand numbers and make sense of the world around us' – Mervyn King, Governor of the Bank of England 'Ifeverypoliticianandjournalistwererequiredtoreadthisengagingandeye-openingbookbeforeembarkingontheir career,wewouldliveinawiser,better-governedworld'–MatthewTaylor,ChiefExecutiveoftheRoyalSocietyof Arts, former chief advisor to the Prime Minister 'Illuminating and comprehensible to even the mathematically challenged' –thefirstpost.co.uk 'Shouldbecompulsoryreading.Itteachescriticalthinkingaboutnumbersandwhattheymeaninahugelyentertain- ing way'– enlightenmenteconomics.com MICHAELBLASTLANDisawriterandbroadcaster,andwasthecreatorofMoreorLessandtheauthorofJoe: The Only Boy inthe World, also published by Profile. ANDREWDILNOTpresentedMoreorLessonBBCRadio4.HeisPrincipalofStHugh'sCollege,Oxford,and formerly the Director of the Institute for Fiscal Studies. The Tiger That Isn't Seeing Through a World of Numbers MICHAEL BLASTLAND & ANDREW DILNOT This expanded edition published in 2008 First published in Great Britain in 2007 by PROFILE BOOKS LTD 3A Exmouth House Pine Street Exmouth Market London EC1R 0JH www.Profilebooks.com Copyright © Michael Blastland and Andrew Dilnot, 2007, 2008 10 9 8 7 6 5 4 3 2 1 Typeset in Palatino by MacGuru Ltd [email protected] Printed and bound in Great Britain by Bookmarque Ltd, Croydon, Surrey The moral right of the authors has been asserted. Allrightsreserved.Withoutlimitingtherightsundercopyrightreservedabove,nopartofthispublicationmaybereproduced,storedorintroducedintoa retrievalsystem,ortransmitted,inanyformorbyanymeans(electronic,mechanical,photocopying,recordingorotherwise),withoutthepriorwrittenper- mission of both the copyright owner and the publisher of this book. A CIP catalogue record for this book is available from the British Library. eISBN 978-1-84668-111-0 Contents Note on the New Edition Introduction 1 Counting: Use Mushy Peas 2 Size: It's Personal 3 Chance: The Tiger That Isn't 4 Up and Down: A Man and his Dog 5 Averages: The White Rainbow 6 Targets: The Whole Elephant 7 Risk: Bring Home the Bacon 8 Sampling: Drinking from a Fire Hose 9 Data: Know the Unknowns 10 Shock Figures: Wayward Tee Shots 11 Comparison: Mind the Gap 12 Correlation: Think Twice Finally … Acknowledgements Further Reading To Catherine, Katey, Rosie, Cait, Julia and Joe Note on the New Edition This expanded and updated edition includes almost all the material from the original, together with a new chapter, numerousnewexamples(includingafewtoshowthatitisnotonlytheUKthatenjoysaculturerichinthemurderous use of numbers), some new tricks, new arguments and old ones sharpened (we hope) by experience, and, finally, a quickchecklistattheend.Italsoallowsusanopportunitytomakeonenewclaim:thatthoughthebookisallabout thewaynumbersareused,itisbestthoughtofasbeingnotaboutnumbersatall,certainlynotaboutnumbersfortheir ownsake.Thekindofnumberswecomeacrosseveryday,thekindexaminedhere,arealwaysameanstoanend;that end being a better understanding of life. Michael B and Andrew D April2008 Introduction Numberssaturatethenews,politics,life.Forgoodorill,theyaretoday'spre-eminentpubliclanguage–andthose who speak it rule.Quick and cool, numbers often seem to have conquered fact. Buttheyarealsohated,oftenforthesamereasons.Theycanbamboozlenotenlighten,terrorisenotguide,andall too easily endup abused and distrusted. Potent but shifty, the role of numbers is frighteningly ambiguous.How can we see our way through them? First, relax … Weallknowmorethanwethinkwedo.Wehavebeenbeautifullyconditionedtomakesenseofnumbers,believeit ornot,byourownexperience.Thisistheradicalpremiseofthisbook–thatreadershavenoneedtothrowuptheir hands in fear or contempt, if only they see how much they know already. Numberscanmakesenseofaworldotherwisetoovastandintricatetogetintoproportion.Theyhavetheirlimita- tions, no doubt, but are sometimes, for some tasks, unbeatable. That is, if used properly. Soalthoughthereisarichstoreofmischiefandscandalhere,itisnottodiscreditnumbersthemselves.Thereare liesanddamnedliesinstatistics,forsure,butscorningnumbersisnoanswer.Forthatistogiveupthegameonevery political, economic or social argument you follow, every cause you love or hate. Ouraimisrathertobringnumbersbacktoearth,notonlybyuncoveringthetricksofthetrade–themultiplecount- ing, dodgy graphs, sneaky start dates and funny scales – there have been exposés of that kind of duplicity before, thoughtherearegemsinthestoriesthatfollow;norbyrelyingonarcanestatisticaltechniques,brilliantthoughthose often are. Instead, wherever possible, we offer images from life – self, experience, prompts to the imagination – to show how to cut through to what matters. It is all there; all of us possess most of it already, this basic mastery of theprinciplesthatgovernthewaynumberswork.Itcanbeshared,wethink,evenbythosewhooncefoundmathsa cobwebbed mystery. Butsimpledoesnotmeantrivial;simplenumbershelpanswerimperativequestions.Doweknowwhatpeopleearn andowe,whoisrichandwhopoor?Isthatgovernmentspendingpromiseworthadime?Wholivesandwhodiesby governmenttargets?Arethoseleaguetableshonest?Dospeedcamerassavelives?Whataboutthatsurveyofteenage offending,the1in4whodothis,the6percentincreaseinriskforwomenwhodothat,inflation,Iraqiwardead,HIV/ Aidscases,howonecountrycompareswithanother,thedeclineoffishstocks,thethreatofcancer,thepensiontime bomb,NHSbudgets,wasteandwaitingtimes,ThirdWorlddebt,UKdebt,predictionsofglobalwarming?Hardlya subject is mentioned these days without measurements, quantifications, forecasts, rankings, statistics, targets, num- bers of every variety; they are ubiquitous, and often disputed. If we are the least bit serious about any of them, we should attempt to get the numbers straight. Thismeanstakingonloftycritics.Toomanyfinditiseasiertodistrustnumberswholesale,affectingdisdain,than get to grips with them. When a well-known writer explained to us that he had heard quite enough numbers, thank you–hedidn'tunderstandthemanddidn'tseewhyheshould–hisobjectionseemedtoustomaskfear.Jealousof hisprejudicesorthefewscrapsofnumericallitterhealreadypossessed,heturneduphisnoseatevidenceincaseit provedinconvenient.Everyonepaysforthisattitudeinbadpolicy,badgovernment,gobblede-gooknews,anditends in lost chances and screwed-up lives. Anotherdragonbetterslainistheattitudethat,ifnumberscannotdeliverthewholetruthstraightoff,theyareall justopinion.Thatdamnsthemwithunreasonableexpectation.Oneofthefewthingswesaywithcertaintyisthatsome ofthenumbersinthisbookarewrong.Thosewhoexpectcertaintymightaswellleavereallifebehind.Everyoneis makingtheirwayprecariouslythroughtheworldofnumbers,nosinglenumberoffersinstantenlightenment, lifeis not like that and numbers won't be either. Stillothersblamestatisticalbean-countersforakindofcrassreductionism,andthinkthey,withsubtletyandsensit- ivity,knowbetter.Thereissometimessomethinginthis,butjustasoftenitistheotherwayround.Moststatisticians know the limits of any human attempt to capture life in data – they have tried, after all. Statistics is far from the drycollectionoffacts;itisthescienceofmakingwhatsubtlesenseofthefactswecan.Nosciencecouldbemore necessary, and those who do it are often detectives of quiet ingenuity. It is others, snatching at numbers, brash or over-confident, who are more naively out of touch. Soweshouldshuntheextremesofcynicismorfear,ontheonehand,andnumberidolatryontheother,andget on with doing what we can. And we can do a great deal. Mostofwhatishereisalreadyusedandunderstoodinsomepartoftheirlivesbyalmosteveryone;weallapply the principles, we already understand the ideas. Everyone recognises, for example, the folly of mistaking one big waveforarisingtideand,sincewecandothat,perhapstooursurprise,wecanunravelargumentsaboutwhether speedcamerasreallysavelivesorcutaccidents.Inlife,wewouldsee–ofcoursewewouldsee–thewaythatfalling ricescattersand,becausewecanseeit,wecanalsomakesimplesenseofthenumbersbehindcancerclusters.We knowthevibrancyofthecoloursoftherainbowandweknowwhatwewouldlackifwecombinedthemtoforma blandwhitebandinthesky.Knowingthiscan,aswewillsee,showuswhatanaveragecanconcealandwhatitcan illuminate–averageincome,forexample.Manyknowfromreadyexperiencewhatitcoststobuychildcare,andso theycanknowwhethergovernmentspendingonchildcareisbigorsmall.Weare,eachoneofus,theobviousand ideal measure of the policies aimed at us. These things we know. And each can be a model for the way numbers work.Allweseektodoisreconnectwhatanyonecanknowwithwhatnowseemsmysterious,reconnectnumbers withimagesandexperiencefromlife,suchthat,ifwehavedoneourjob,whatoncewasbafflingorintimidatingwill become transparent. What follows will not be found in a textbook: even the choice and arrangement of subjects would look odd to aspecialist,letalonethewaytheyarepresented.Good.Thisisabookfromthepointofviewoftheconsumerof numbers.Itisshortandtothepoint.Eachchapterstartswithwhatweseeasthenubofthematter:aprinciple,or avividimage.Wipethementalslatecleanofanxietyorfuzzinessandinscribeinsteadtheseideas,keepeachmotif inmindwhilereading,seehowtheyworkinpracticefromthestorieswetell.Inthiswaywehopetolightthepath towards clarity and confidence. Thealignmentofpowerandabuseisnotuniquetonumbers,butitisjustpossiblethatitcouldbeuniquelychal- lenged, and the powerless become powerful. Here's how.
The list of books you might like
