%macro mcartest;
/* PROVIDE VALUES FOR THE FOLLOWING MACRO VARIABLES */
%let datafile = "C:\Users\Bharat\Desktop\7037 Project\hbat_missing_new"; * FILE PATH FOR RAW DATA;
%let numvars = 26; * NUMBER OF VARS IN DATA FILE;
%let misscode = .; * SPECIFY MISSING VALUE CODE;
%let varnames = v1_miss v2_miss v3_miss v4_miss v5_miss; * SPECIFY VARIABLE NAMES;
%let seednum = 564321; * SPECIFY RANDOM SEED;
/* DO NOT ALTER THE CODE BELOW */
data one;
infile &datafile ;
input &varnames ;
array m[&numvars] &varnames ; array r[&numvars] r1 - r&numvars ;
do i = 1 to &numvars;
if m[i] = &misscode then m[i] = .;
end; drop i;
do i = 1 to &numvars;
r[i] = 1;
if m[i] = . then r[i] = 0;
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end; drop i;
proc sort;
by r1-r&numvars;
proc mi data = one seed = &seednum nimpute = 0 noprint;
var &varnames;
em outem = emcov;
proc iml;
use one; read all var {&varnames} into y;
read all var {%do i = 1 %to &numvars; r&i %end;} into r;
use emcov; read all var {&varnames} into em;
mu = em[1,]; sigma = em[2:nrow(em),];
/* ASSIGN AN INDEX VARIABLE DENOTING EACH CASE’S PATTERN */
jcol = j(nrow(y), 1 , 1);
do i = 2 to nrow(y);
rdiff = r[i,] - r[i - 1,];
if max(rdiff) = 0 & min(rdiff) = 0 then jcol[i,] = jcol[i - 1,];
else jcol[i,] = jcol[i - 1,] + 1;
end;
/* NUMBER OF DISTINCT MISSING DATA PATTERNS */
j = max(jcol);
/* PUT THE NUMBER OF CASES IN EACH PATTERN IN A COL VECTOR M */ /*
PUT THE MISSING DATA INDICATORS FOR EACH PATTERN IN A MATRIX RJ */
m = j(j, 1, 0); rj = j(j, ncol(r), 0);
do i = 1 to j;
count = 0;
do k = 1 to nrow(y);
if jcol[k,] = i then do;
count = count + 1;
end;
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if jcol[k,] = i & count = 1 then rj[i,] = r[k,];
m[i,] = count;
end;
end;
/* COMPUTE D^2 STATISTIC FOR EACH J PATTERN */
d2j = j(j, 1, 0);
do i = 1 to j;
/* OBSERVED VALUES FOR PATTERN J */
yj = y[loc(jcol = i),loc(rj[i,] = 1)];
/* VARIABLE MEANS FOR PATTERN J */
ybarobsj = yj[+,]/nrow(yj);
/* D = P X Pj MATRIX OF INDICATORS (SEE P. 1199) */
Dj = j(ncol(y), rj[i,+], 0);
count = 1; do k = 1 to ncol(rj);
if rj[i,k] = 1 then do;
Dj[k, count] = 1;
count = count + 1;
end;
end;
/* REDUCE EM ESTIMATES TO CONTAIN OBSERVED ELEMENTS */
muobsj = mu * Dj; sigmaobsj = t(Dj) * sigma * Dj;
/* THE CONTRIBUTION TO THE D^2 STATISTIC FOR EACH OF THE J PATTERNS
*/
d2j[i,] = m[i,] * (ybarobsj - muobsj) * inv(sigmaobsj) * t(ybarobsj
- muobsj);
end;
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/* THE D^2 STATISTIC */
d2 = d2j[+,];
/* DF FOR D^2 */
df = rj[+,+] - ncol(rj); p = 1 - probchi(d2,df);
/* PRINT ANALYSIS RESULTS */
file print; put "Number of Observed Variables = " (ncol(rj)) 3.0;
put "Number of Missing Data Patterns = " (j) 3.0; put; put "Summary
of Missing Data Patterns (0 = Missing, 1 = Observed)"; put; put
"Frequency | Pattern | d2j"; put; do i = 1 to nrow(rj);
put (m[i,]) 6.0 " | " @;
do j = 1 to ncol(rj);
put (rj[i,j]) 2.0 @;
end;
put " | " (d2j[i,]) 8.6;
end; put; put "Sum of the Number of Observed Variables Across
Patterns (Sigma psubj) = " (rj[+,+]) 5.0; put; put "Little’s (1988)
Chi-Square Test of MCAR"; put; put "Chi-Square (d2) = " (d2)
10.3; put "df (Sigma psubj - p) = " (df) 7.0; put "p-value
= " (p) 10.3;
%mend mcartest;
%mcartest;
run;