ROC曲线下AUC值

还是没有人给出具体做法吗？敬请帮助啊。

%macro ROC(variable=,binary=,intable=,outtable=);
option notes=1;
proc sql;
    create table &outtable.
    (FLAG char(20)
    ,VAR char(20)
    ,ROC  num
    ,constraint ok_roc  check(roc  between 0.5 and 1)
    );
quit;
proc sql noprint;
    create table temp_1 as
    select &variable.,count(*) as bin_sum ,sum(&binary.) as bin_resp from &intable.
    where  &variable. is not null
    group by &variable.
    order by &variable.;
    select count(*)-sum(&binary.) into :total_nresp from &intable. where &variable. is not null;
    select sum(&binary.) into :total_resp from &intable. where &variable. is not null;
quit;
data temp_2;
    set temp_1;
length area 8.;
retain C_sum 0 C_resp 0  C_nresp 0 l_resp 0 l_nresp 0;
    C_sum=sum(C_sum,bin_sum);
    C_resp=sum(C_resp,bin_resp);
    C_nresp=C_sum-C_resp;
    _sensit=C_resp/&total_resp.;
    _1mspec=C_nresp/&total_nresp.;
    area=(C_nresp-l_nresp)/&total_nresp.*(C_resp+l_resp)/&total_resp./2;
    l_resp=C_resp;
    l_nresp=C_nresp;
run;
proc sql;
    insert into &outtable.
    select
       distinct "&binary." as FLAG,
       "&variable." as VAR,
       case when sum(a.area) ge 0.5 then sum(a.area)
   else 1-sum(a.area) end as ROC
from temp_2 as a;
quit;
proc sql;drop table temp_1,temp_2;quit;
%mend;
%ROC(variable=诊断指标,binary=二值变量,intable=要检验的数据集,outtable=输出数据集);

求AUC的其中一种方法，可以根据多个sensitivity, 1-specificity对应的点，来计算多个梯形的面积，当然，最接近0的那个是三角形，再求和，就是AUC了，用SAS实现的话，比较简单。

用SPSS画出的ROC曲线图输出结果中已直接给出AUC的值