SAS Day 40: Forest Plot

Tired looking across many overall response tables while comparing the same rate? The **forest plot** is a perfect solution to **summarise data from multiple resources and convert it into a single reader-friendly graph**.

**Ideal Forest Plot:**

When taking all the relevant studies, ask the same question with the same statistical model, identifies a common endpoint in papers and displays them on a single set of axis. The forest plot directly comparing the studies by showing the quantity and quality of the results all in one place.

(🔷 means the most important study, and ⚫ size is according to the study population size)

Done is better than perfect, so we will do a practical forest plot example.

**Practical Forest Plot:**

Instead of gathering all the relevant studies, we will compare the Overall Survival Rate different categories (Age group, Sex, Hispanic).

**Interpretation:**

The Forest plot did not show one category has significant Overall response rate than another, but Non-Hispanic group did show a little edge in the treatment. The **blue dot** is the Calculated 95% Confidence Interval based on the data. The red interval is the** range of values within which you can be 95% certain the true value lies.**

#### SAS Sample Dataset

proc sort data=crr out=crr1; by descending ord; run;

*graph; options orientation=landscape; ods graphics on/ height=400px width=600px; ods pdf nogfootnote nogtitle ; title1 j=center "Graph 1"; title2 j=center " Forest Plot for Overall Response Rate"; title3 j=center "x Population"; proc sgplot data=orr1; scatter x=oc1 y=lbl /xerrorlower=clow xerrorupper=chigh markerattrs=or (symbol=CirleFilled size=4); refline 40 /axis=x; xaxis values=(0 to 100 by 20) display=(nolabel); yaxis valueattrs=(size=8pt) display=(nolabel); yaxistable c3/ label="ORR(95% CI)" location=inside ; run; goptions reset=all; ods pdf close; ods listing;

**Happy Practicing** and i decide to use a recycle bag to shopping today, so save some trees to make a forest plot!

**Reference:**

https://www.students4bestevidence.net/tutorial-read-forest-plot/