*! version 1.0.0 (STB-33: sg59)
program define iov
    version 4.0
    local varlist "req ex"
    local if "opt"
    local in "opt"
    local options "Rows(int 5) Actual"
    parse "`*'"
    parse "`varlist'", parse(" ")
    tempvar kant touse

preserve
qui mark `touse' `if' `in'
qui keep if `touse'

if "`actual'"=="" {
    di ""
    di "Variable" _col(12) "IOV" _col(25) "IOC" _col(40) "p-value"
    di in gr _dup(9) "-" "+" _dup(36) "-"

    while "`1'" != "" {
    qui egen `kant'=group(`1')
         local tee=0
         local i=1
         qui ta `1'
         local en=_result(1)
         qui {
              while `i' < `rows' {
                   local k=1
                   while `k' < `rows' {
                        count if `kant'==`i'
                        local c1=_result(1)
                        count if `kant'==`i'+`k'
                        local c2=_result(1)
                        local tee=`tee'+(`c1'*`c2'*((`k'+`i')-`i'))
                        local k=`k'+1
                   }
              local i=`i'+1
              }
         }
    if mod(`en'/2,1)>.4 {
         local tmax=((`en'^2 - 1)*(`rows' - 1))/4
    }
    else { local tmax=((`en'^2)*(`rows' - 1))/4 }
    local iov = `tee'/`tmax'
    local ioc = 1 - `iov'
    local ex=`en'/`rows'
    local g=1
    local gof=0
    qui nbgof `1' `if' `in'
    di "`1'" _col(10) in gr "|" _col(12) in ye %6.4f `iov' _col(25) /*
      */ %6.4f `ioc' _col(40) %5.4f $S_2
    qui drop `kant'
    mac shift
    }
}

else {
    di ""
    di "Variable" _col(12) "IOV" _col(25) "IOC" _col(40) "p-value" _col(55) /*
         */ "rows"
    di in gr _dup(9) "-" "+" _dup(48) "-"

    while "`1'" != "" {
    qui egen `kant'=group(`1')
         local tee=0
         local i=1
         qui ta `1'
         local en=_result(1)
         local rows=_result(2)
         qui {
              while `i' < `rows' {
                   local k=1
                   while `k' < `rows' {
                        count if `kant'==`i'
                        local c1=_result(1)
                        count if `kant'==`i'+`k'
                        local c2=_result(1)
                        local tee=`tee'+(`c1'*`c2'*((`k'+`i')-`i'))
                        local k=`k'+1
                   }
              local i=`i'+1
              }
         }
    if mod(`en'/2,1)>.4 {
         local tmax=((`en'^2 - 1)*(`rows' - 1))/4
    }
    else { local tmax=((`en'^2)*(`rows' - 1))/4 }
    local iov = `tee'/`tmax'
    local ioc = 1 - `iov'
    local ex=`en'/`rows'
    local g=1
    local gof=0
    qui nbgof `1' `if' `in'
    di "`1'" _col(10) in gr "|" _col(12) in ye %6.4f `iov' _col(25) /*
      */ %6.4f `ioc' _col(40) %5.4f $S_2 _col(56) %3.0f `rows'
    qui drop `kant'
    mac shift
    }
}
end
exit

----+----1----+----2----+----3----+----4----+----5----+----6----+----7
           IOV          IOC            p-value
---------|-----------------------------------------------------------------