Hello,
I applied Amelia II to multiply impute missings in our survey data. I used AmeliaView and
the imputation was successful, so Amelia generated five sets of multiply imputed data in
Stata (dta) format (that I had chosen).
After the multiple imputation I conducted a few sets of regression analyses using
"Clarify" to combine the results across the five multiply imputed data. The
analyses also worked well,the coefficients all make sense (they correspond with the other
analyses we have done using "observed" data) but a problem is some of the
analyses sometimes yielded exceptionally high degrees of freedom for some variables. I
don't know why I got this inflated degrees of freedom because all procedures went
well without any error messages (not every variables but some of the variables included
yielded high degrees of freedom). For your information, I didn't have any other
problems other than this.
With regard to this, I emailed to Matt and was advised to use Zelig for data analysis (and
I will try to do that) but still wonder about these generally high degrees of freedom
issue.
I attached the some of the results from our analysis below (sorry about very-long variable
name, it tracks our record of changes), so if any of you can give us any reasons for this,
it will be greatly appreciated !!!
Thanks a lot!
*Model 4
estsimp ologit Academic_Rank female_excludes_missing Minority_excludes_missing
MarriedPartnered childrennumber_excluding_missng ///
Partner_employed_fulltime ProgramRankReversed YearsToDegree_b Q18Specified_1a
Overalladvise ///
Q24a_1 Joint_appt_exclude_missing Private_Instit_excluding_missng
PHD_program_excluding_missing MA_program_excluding_missing ///
CurrentDepartmentRank Overallresource Released_from_teaching Age, ///
mi(Amelia_07081 Amelia_07082 Amelia_07083 Amelia_07084 Amelia_07085)
Ologit estimates (via multiple imputation) Nobs = 1274
---------------------------------------------------------------
Academic_Rank | Coef. Std. Err. t d.f. P>|t|
---------+-----------------------------------------------------
female~g | -.3274721 .166179 -1.971 46 0.055
Minori~g | -.2167513 .2327173 -0.931 21 0.362
Marrie~d | .1626777 .2992682 0.544 13 0.596
childr~g | -.0014547 .0611694 -0.024 1369 0.981
Partne~e | .1729933 .1713316 1.010 66 0.316
Progra~d | .0937531 .0533029 1.759 737 0.079
YearsT~b | -.1231956 .0332016 -3.711 326 0.000
Q18Sp~1a | -.031667 .0363591 -0.871 140 0.385
Overa~se | .255504 .1046298 2.442 391 0.015
Q24a_1 | .3497809 .0661697 5.286 107 0.000
Joint_~g | .240031 .2157427 1.113 884 0.266
Privat~g | .1729383 .1528752 1.131 1393 0.258
PHD_pr~g | -.4210008 .2339427 -1.800 450 0.073
MA_pro~g | -.5302672 .1984522 -2.672 228 0.008
Curren~k | .0081537 .0687515 0.119 962 0.906
Overa~ce | .0831138 .0275379 3.018 227 0.003
Releas~g | .1378443 .0192077 7.177 8560 0.000
Age | .1728987 .0092188 18.755 107 0.000
_cut1 | 7.459078 .5828492 12.798 175 0.000
_cut2 | 9.781068 .6282563 15.569 175 0.000
---------------------------------------------------------------
Number of simulations : 1000
Names of new variables : b1 b2 b3 b4 b5 b6 b7 b8 b9 b10 b11 b12 b13 b14 b15 b16 b17 b18
b19 b20
Datasets used for MI : Amelia_07081 Amelia_07082 Amelia_07083 Amelia_07084 Amelia_07085
Lee, Jaemook
The University of Iowa
Ph.D Candidate
Department of Political Science
Iowa City, Iowa,
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