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st: RE: Why stata 7 and stata 8 give out different answers


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: RE: Why stata 7 and stata 8 give out different answers
Date   Sun, 25 Apr 2004 17:16:09 +0100

Possibly not the issue, but don't use 

local varlist1 = " < long list> " 

when you are just copying from right to left. You 
are likely to get bugs, because lists will be truncated
at 80 characters. See help on -limits-: see limits 
of length of string expression 

Nick 
n.j.cox@durham.ac.uk 

Maoyong Fan
 
> I wrote a very simple program and run it on both Stata 7 
> intercool and Stata 8 SE, but they give me different answers.
> 
> The reason is that they drop different variables.
> 
> I wonder why is this.  Should they do the same job since I 
> use the exact same program and data set?
> 
> Program:
> 
> clear
> 
> set memory 200m
> ***set maxvar 2048
> set more off
> set rmsg on
> 
> set logtype text
> set linesize 200
> 
> ***Course 32 matching estimator
> 
> use pdp_matching.dta, clear
> keep	coalition_pool verbal_sat math_sat eop_status hs_gpa 
> father_educ mother_educ language_code english non_english 
> ethnic	admit_major math_physics	econ_business	
> chemistry	biology	engineering	c32_lecture	
> c32_times_taken	c32_year	c32_term	
> c32_num_grade	c32_math_98	c32_pdp_ids	
> c32_pdp_ids_not_pass	c32_slc_adjunct	
> c32_slc_adjunct_not_pass		pdp	slc	
> pdp_coalition_pool
> 
> drop  if    coalition_pool  ==  .
> drop	if	verbal_sat	==	.
> drop	if	math_sat	==	.
> drop	if	eop_status	==	.
> drop	if	hs_gpa	==	.
> drop	if	father_educ	==	.
> drop	if	mother_educ	==	.  
> drop	if	language_code	==	.  
> drop	if	english	==	.
> drop	if	non_english	==	.
> drop  if    ethnic  ==      .
> drop  if    ethnic  ==      9
> drop	if	admit_major	==	.
> drop	if	math_physics	==	.
> drop	if	econ_business	==	.
> drop	if	chemistry	==	.
> drop	if	biology	==	.
> drop	if	engineering	==	.
> drop	if	c32_lecture	==	.
> drop	if	c32_year	==	.
> drop	if	c32_term	==	. 
> drop	if	c32_num_grade	==	.
> 
> drop    if      slc == 1
> 
> keep    if      ethnic == 1
> 
> 
> keep  if c32_num_grade < 5 | c32_num_grade==6 | c32_num_grade==7
> replace c32_num_grade=0 if c32_num_grade<=1.3 | c32_num_grade==7
> replace c32_num_grade=1 if c32_num_grade>=1.7 | c32_num_grade==6
> 
> generate same_class = c32_year*100 + c32_term*10 + c32_lecture
> 
> local varlist_1 = "math_sat	eop_status	hs_gpa	
> father_educ	mother_educ	english		non_english	
> math_physics	econ_business	chemistry	biology	engineering"
> local varlist_2 = "verbal_sat"
> 
> foreach var of local varlist_1 {
> egen `var'_max = max(`var')
> egen `var'_min = min(`var')
> if `var'_max ~= `var'_min  {
> 
> local varlist_2 = "`varlist_2' `var'"
> di "keep `var'"
> }
> else {
> display "drop `var'"
> 
> }
> }
> display "Finish dropping"
> 
> 
> egen pdp_sum = sum(pdp)
> 
> describe
> 
> }
> 
> log close

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