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How to Display Data- P21

How to Display Data- P21:The best method to convey a message from a piece of research in health is via a fi gure. The best advice that a statistician can give a researcher is to fi rst plot the data. Despite this, conventional statistics textbooks give only brief details on how to draw fi gures and display data. | 92 How to Display Data Figure 8.2 Scatterplot and lowess smoothing plot of monthly prescriptions for non-SSRIs antidepressants for a general practice over 22 months from 2002 to 2006 Senior J. Personal Communication 2006 a without lowess smoothing plot and b with lowess smoothing plot. Time series plots and survival curves 93 8.4 Survival The major outcome variable in many clinicaltrials isthe time from ran -domtaa and stori of licalnient In a specified cnfical event. The length of time from entry to the study to when the critical event occurs is called the survival time.Examplesinclude patientsittvival timejtime from diagnosis to death lengthefSlmethatanlndwrUingcepnula temaini enriSu ortha time a seriousbum tskea to leeal. Even wSewat hef nc l ouicomeietioi an actual survsval time-tVstechniquss emplogedwith avap Pime-to- eenuiSslals are conventis nalty aermtd ausvinal anelyrk methods.Anlmvortanteetasnre of such dataisthe sansvaedakservsaSe p which relattaSa paopltwpv tsvs not suffered aneaenP. Censure ngbstatativwa can Sappen aeSvta ilvli f l known follew-up time.lkpiansa are Soei Po follow-up.orShepore tamovpd from the at ris aO i foeaomeolnst redsom Altrrnativelyi si-aescep vcpvi if at the last Pn awn asOow- up tun e a num Pep dO lubietts remain who Save not had an vkpnt. More triad e arsgivanm Whaottrli of Cpmpbell etal.3 The connapVonaS jeeotSVie sueoSvMnalp is tteaKapCan-Meiec saevivat plaS. This plots the proportionkP a are pp turvivmx on the Sdcnis ageansttsme on the X-axis apdaetonr Spccensoredobreovationp. kegure e.V showpa tnuiatd Figure 8.3 Kaplan-Meier survival plot of 25-year follow-up of slate workers n 726 and controls n 529 .- 94 How to Display Data plot which displays the survival of 726 slate workers from 1975 to the present day compared tothe sur2ivalof529 controls who were matched by age and smoking habit.4 Interestingly the slate workers appear to have better survival than the controls. However-there arn a number ofproblomswitlr thir typerf .