*! version 1.0.0 -- STB-11 ip3.1
program define hinflu 
	version 3.0
	if "$S_E_cmd"~="fit" { error 301 }
	tempvar Hi
	local varlist "required new max(1)"
	parse "`*'"
	rename `varlist' `Hi'
	tempvar hii ei di2 
	quietly {
		fpredict `hii', hat
		fpredict `ei', resid
		quietly fit 
		gen `di2'=(`ei'*`ei')/_result(4)
		replace `Hi' = /*
			*/ ((_result(3)+1)/(1-`hii'))*(`di2'/(1-`di2')) + /*
			*/ `hii'/(1-`hii')
	}
	rename `Hi' `varlist'
end