请问desc 和'order=data'什么意义，怎么确定里面的对照组？
ods select none;
  ods trace on; ods listing close;
  proc logistic data=x_all1 desc order=data;
    class  flres1 age1 sex ecogres1  tfld1 eln siteid_;
    model visn=flres1 age1 sex ecogres1  tfld1 eln  siteid_/expb;
/*   ods output  ModelInfo= ModelInfo;*/
/*   ods output  NObs=NObs;*/
/*   ods output  ResponseProfile=ResponseProfile;*/
/*   ods output  ClassLevelInfo= ClassLevelInfo;*/

/*   ods output   ConvergenceStatus= ConvergenceStatus;*/
/*   ods output   CumulativeModelTest= CumulativeModelTest;*/
/*   ods output   FitStatistics= FitStatistics ;*/
    ods output   GlobalTests= GlobalTests;
    ods output   Type3= Type3;
/*    ods output   Association= Association  ;*/
    ods output   OddsRatios= OddsRatios ;
    ods output   ParameterEstimates=ParameterEstimates;
  run;
  ods trace off;
  ods select all;

  data GlobalTests;set GlobalTests;
     if test='Likelihood Ratio';
     keep ProbChiSq;
  run;
  data  Type3;set Type3( keep=Effect ProbChiSq);
     rename  ProbChiSq=bianlP Effect=variable;
/* col0='';*/
  n=_N_;
  proc sort; by variable ;
  run;
  data  OddsRatios ;set OddsRatios ;run;
  data  ParameterEstimates;set ParameterEstimates(keep=variable Estimate StdErr ProbChiSq);
     if Variable^='Intercept';
  rename  ProbChiSq=yaP;
  run;