/*Prodclin.sas - MacKinnon, Fritz, Williams, and Lockwood, 2005       */
/*Dept. of Psychology, Arizona State University                       */
/*Necessary files:prodclin.sas, prodclin.exe                          */

/*The prodclin program calculates asymmetric confidence intervals for */
/*the mediated effect using the distribution of the product of two    */
/*random variables and the Fortran program Prodclin.exe.  To run, open*/
/* in SAS or copy and paste the code into a SAS editor window.  Then, */
/*the location of the Fortran program needs to be entered in four     */
/*places(both files should be in the same location).  Next, values for*/
/*the a and b paths, as well as the standarderrors of a (sea) and b   */
/*(seb) must be input in the macro call line at the end of the        */
/*program.  Lastly, values for rho (correlation between a and b, in   */
/*most cases equal to zero) and alpha (the type 1 error rate) must be */
/*specified in the beginning of the program. Output consists of the   */
/*user specified values for a, sea, b, seb, rho, alpha, ab, the first */
/*order standard error (sobelse), the lower and upper standardized    */
/*critical values from Prodclin [low,high], the asymmetric confidence */
/*limits [prodlow,produp] and the corresponding normal theory         */
/*confidence limits [normlow,normup]. If either prodlow or produp is  */
/*equal to 99999, there was a problem with convergence in the Fortran */
/*program.  First, check the values you input and then, if the problem*/
/*still occurs, try using fewer decimal places.                       */


/*All places that need user input have been labeled with comments.    */

options noxwait;

*Input values for rho and alpha;
%let rho=0;
%let alpha=.05;

%macro prodclin(a, sea, b, seb);
data data1; 
*Change file address to match the location of the file prodclin.exe;
file "G:/raw.txt";
a=&a; sea=&sea; b=&b; seb=&seb; rho=ρ alpha=α
put a @; put sea @; put b @; put seb @; put rho @; put alpha @;data data1;

*Change file address to match the location of the file prodclin.exe; 
X cd G:/;
*Change file address to match the location of the file prodclin.exe;
X call "G:/prodclin.exe";

data data2; 
*Change file address to match the location of the file prodclin.exe;
infile "G:/critval.txt";
input lcrit ucrit;
a=&a; sea=&sea; b=&b; seb=&seb; rho=ρ alpha=α
da=a/sea;
db=b/seb;
sedadb=sqrt(da*da+db*db+1);
dadb=da*db;
low=(lcrit-dadb)/(sedadb);
high=(ucrit-dadb)/(sedadb);
ab=a*b;
sobelse=sqrt(a*a*seb*seb+b*b*sea*sea);
prodlow=ab+low*sobelSE;
produp=ab+high*sobelSE;
nl=probit(alpha/2);
normlow=ab+nl*sobelse;
normup=ab-nl*sobelse;
if lcrit=99999 then prodlow=99999;
if ucrit=99999 then produp=99999;

proc print data=data2 noobs; 
var a sea b seb ab sobelse rho alpha normlow normup low high prodlow produp;
run;

%mend;
*Input values for a, st. error a, b, st. error b;
*%prodclin(a=.3937, sea=.1872, b=-.8798, seb=.1910);*PHLAME example;
%prodclin(a=.1701, sea=.0156, b=.1998, seb=.0364);*Duncan et al example;
run;
quit;