Hi Folks: I've never used proc iml before and trying to use the approach suggested in the Wicklin's blog.  I have a dataset with a variable with negative values which needs to be log transformed.  data have; input var; cards; -1 -2 ;  And this step was suggested. Can you help me understand how I am supposed use the proc iml approach suggested so that variable 'var' with negative values in my 'have' dataset is translated and log transformed?  proc iml; Y = {-3,1,2,.,5,10,100}; /* negative datum */ LY = log10(Y + 1 - min(Y)); /* translate, then transform */ https://blogs.sas.com/content/iml/2011/04/27/log-transformations-how-to-handle-negative-data-values.html ... View more

Hi Folks: I'm trying to create Kaplan Meier plots and COX-PH modelling eventually. I have two questions for you since these two problems maybe related to a single error, I gut.  1. I defined the DURATION variable (time until death since diagnosis confirmed)  and vital_status as shown below where vital_status=1 indicates the event of death. Based on my reading, I think defining  time duration*vital_status(0); in the proc lifetest and proc phreg is the correct way. However, the resulting plot doesn't make sense because the medical condition concerned is highly fatal and the plot produce where vital_status(1) is close to the survival pattern. Why this could happen? 2. Also, the minimum and maximum survival time among the deceased are: 0 and 21. However, my plots show 70 which is the max follow-up time censored by 22004 which is the end of study date.  Could you please let me know your suggestions to address these problems?  Thank you for your time and help indeed.      IF DECEASED_DATE NE . THEN DEATH_DATE=DECEASED_DATE; ELSE IF DECEASED_DATE=. THEN DEATH_DATE=22004; DURATION=DEATH_DATE-CONFIRMED_DATE; if state='deceased' then vital_status=1; else vital_status=0;     ... View more

Hi Folks:   I'm trying to present the values in histogram such that value labels define the border of each bar as shown in the image below for the first two bars for example. Right now, the numbers are placed at the middle of each bar which is not that helpful for a particular task I have in hand.    Thanks for your time indeed.  proc univariate data=sashelp.air; var air; histogram; run;     ... View more

Hi Folks:   I'm trying Cox PHM in an infectious disease sample (N=2,765) where number of events (death) is only N=48. My covariates include age groups by 10 years, gender and comorbidity (yes,no) with missing.  My questions are: 1. Is Cox PHM is the good choice here? I tried log-rank tests but I wanted to have hazard estimates for all covariates included and accounted in the model at the same time.  2. Shall I delete the observations for age groups with no events (death). The model output suggests that the observations with missing in age groups have not been used in the parameter estimation anyway?   ... View more