Hello,

I'm new to Stata. I'm working on a Cox regression analysis (also new to this) on quite a large dataset. When I check the PH assumption, I would like to save the graphs for each covariate (age_cat, n_31_0_0, townsend_5 and education), then combine the graphs together and export as a pdf. Is that possible? and if so, how would I go about it? I've had a look at other posts on this site but cannot get my head around them.

For example, after I enter the below, I would like to combine the graphs and export:
Code:
stset censoroesoph, failure(inc_oesoph) id(n_eid) scale(365.25) origin(ts_53_0_0)
* Model 1
stcox i.n_23074_0_0 i.age_cat i.n_31_0_0 i.townsend_5 i.education,base
* Check PH assumption
stphtest, detail
estat phtest  
stphplot, by(age_cat)
graph save oesoph1age_cat
stphplot, by(n_31_0_0)
graph save oesoph1sex
stphplot, by(townsend_5)
graph save oesoph1townsend_5
stphplot, by(education)
graph save oesoph1education
However, when I try to use the graph combine command, this is what I get:
Code:
graph combine oesoph1age_cat.gph oesoph1sex.gph oesoph1townsend_5.gph oesoph1education.gph
file oesoph1age_cat.gph not found
Any help would be much appreciated, thank you.