Hi, I am a little stuck with creating a Bland-Altmann plot. I have used the following script : https://www.tutorialspoint.com/sas/sas_bland_altman_analysis.htm However when I create the graph, no upper limit or mean reference line is displayed. Here is the code I have used and attached you can find the values for the 2 methos I wish to compare : ************************************************ ** Get the mean and standard deviation of the ** ** difference Method1-Method2. ** ************************************************; proc means data=diffs mean std noprint; var diff_carb; output out=mdiff mean=mdiff_carb std=sddiff_carb; run; proc print data = mdiff ; run; ************************************************* ** Merge the mean and standard deviation of the ** ** difference with each observation in the ** ** original data file. ** *************************************************; data datafile2; if _n_=1 then set mdiff; set diffs; lldiffm1m22=mdiff_carb-(2*sddiff_carb); uldiffm1m22=mdiff_carb+(2*sddiff_carb); drop _freq_ _type_; run; proc print data = datafile2; run; ******************************************************************** ** Create the Bland Altman Plot with ** ** scatter of the difference vs the mean for each observation ** ** a reference line at 0 in solid blue ** ** a reference line at the mean of the difference in solid red ** ** a reference line at +/- 2SD of the mean of the difference in ** ** dashed red ** ********************************************************************; proc sgplot data=datafile2; scatter x=mean_carb y=diff_carb; refline uldiffm1m22 / axis=y lineattrs=(color=red pattern=4 thickness=2pt) label = "95% upper limit" ; refline lldiffm1m22 / axis=y lineattrs=(color=red pattern=4 thickness=2pt) label = "95% lower limit" ; refline mdiff_carb / axis=y lineattrs=(color=red thickness=2pt) label = " mean difference " ; refline 0 / axis=y lineattrs=(color=blue thickness=2pt) label = "zero bias "; yaxis label='Difference (MFPQC-Nubel)'; yaxis values = (-95 35 ) ; xaxis label='Mean (MFPQC+Nubel)/2'; title 'Bland-Altman Plot of Difference (MFPQC-Nubel) vs Mean'; run; Thank you!!
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