# C. R. Charig et al. 1986. Br Med J (Clin Res Ed) 292: 879–882
# Treatment A: all open procedures
# Treatment B: percutaneous nephrolithotomy
# Question: which treatment is better?
Treat	Success	StoneSize	Freq
A	Yes	Small	81
A	No	Small	6
B	Yes	Small	234
B	No	Small	36
A	Yes	Large	192
A	No	Large	71
B	Yes	Large	55
B	No	Large	25