Amelia July 2003

amelia@lists.gking.harvard.edu

5 participants
4 discussions

L os- in-g w.ei- gh_ t i- mp-os_si .bl_ e?

by Jerry Askew

Thought about you when I got this, sounds a lot like what you were refering to. http://www.finditnowandhere.com/guest.htm They've got over 250 kinds of cheap brand name smokes & send them to you with no shipping cost. Once you've seen it get ahold of me, I want to hear your reaction - you'll go batty I know it. Tell me when you get back. Erich

20 years, 8 months

Problem with variable names

by Strom C. Thacker

Hello, I am attempting a TSCS imputation, and am having the same problems that others have had in the past with a AMvarnm error message that reads as follows: "_AMvarnm has too many variable names to match each variable in the dataset. Delete variable names, or set _AMvarnm=. for default variable names (default = var1 var2 . . .)." I'm using version 2.0 (7/15/01) for Windows, and the only options I have set are as follows: AMts=1 AMcs=2 AMlagvs=3 AMtstep=1 I've left all else at the default settings. FWIW, I also tried it with various AMempri settings, and got the same error message. Finally, I tried it without declaring it a TSCS dataset just to see if it would run (using the default on all options), and it did. Any suggestions? Thanks, Strom

20 years, 9 months

RE: Way to Do Missing Value Imputation But Also Have Structurally Missing Data Unhampered?

by Feinstein, Zachary

Thanks for the reply. Indeed you are correct about the "are you pregnant" analogy. There is no sensible answer to those questions for those people. Your solution to just impute everything, then know that particular cells is intriguing. On one hand, it is quite simple. On the other hand, I was under the impression that an iterative process went on behind the scenes in estimating the missing values. Your response leads me to believe that it is iterative in the sense that it only uses information from data that exists and does not substitute, then go through another iteration (think of a cluster analysis procedure where people are first assigned, then can move around a bit, depdenting upon what procedure you are using). Once again, many thanks for getting back with me so quickly. Zachary -----Original Message----- From: Gary King [mailto:king@harvard.edu] Sent: Friday, July 11, 2003 9:14 PM To: Feinstein, Zachary Cc: Amelia Listserv Subject: Re: Way to Do Missing Value Imputation But Also Have Structurally Mis sing Data Unhampered? a structural missing element would be the answer to the question "are you pregnant?" and the respondent is male. you don't ask the question because there is no sensible random variable that this answer would produce. if you havethis kind of problem, thenyou could merely impute this along with the rest but ignore the imputations for the structural zeros. however, maybe what you have instead is just questions you decided not to ask some respondents for lack of time. this is often called matrix sampling, and there's no problme both imputing and using theimputations from this setup. in fact, since you determine the missingness pattern, you know that the asumptions of amelia apply (assuming you choose the respondents in a sensible way of course). Gary On Fri, 11 Jul 2003, Feinstein, Zachary wrote: > I have a dataset of let's say 200 respondents by 10 variables. This is for > market research. Occasionally people say Don't Know or state they do not > wish to respond to certain questions. For the analyses I will be using the > results for, I need to estimate the missing data here. A poor-person's way > of doing it would be mean-substitution. > > Note that certain groups of people were not asked certain questions though > based on skip patterns. I cannot remove their column or row from the 200 X > 10 matrix and I still wish to figure what to do? > > Note that the scales are ordinal/continuous from 1 to 10. I made it so that > if they said Don't Know, the data becomes missing. I used zeroes to define > the cells where it is structurally missing and quite Kosher. Perhaps I > should use a character to make it explicit that it is not part of the scale > in the future. > > Any help on how to use Amelia with this kind of situation is greatly valued > and appreciated. Thank you. > > -- > Zachary S. Feinstein > Methodologist > Harris Interactive > zfeinstein(a)harrisinteractive.com > http://www.harrisinteractive.com > phone: (952) 541-7161 > > 435 Ford Road, Suite 250 > Minneapolis, MN 55426 > >

20 years, 9 months

Re: Way to Do Missing Value Imputation But Also Have Structurally Mis sing Data Unhampered?

by Gary King

a structural missing element would be the answer to the question "are you pregnant?" and the respondent is male. you don't ask the question because there is no sensible random variable that this answer would produce. if you havethis kind of problem, thenyou could merely impute this along with the rest but ignore the imputations for the structural zeros. however, maybe what you have instead is just questions you decided not to ask some respondents for lack of time. this is often called matrix sampling, and there's no problme both imputing and using theimputations from this setup. in fact, since you determine the missingness pattern, you know that the asumptions of amelia apply (assuming you choose the respondents in a sensible way of course). Gary On Fri, 11 Jul 2003, Feinstein, Zachary wrote: > I have a dataset of let's say 200 respondents by 10 variables. This is for > market research. Occasionally people say Don't Know or state they do not > wish to respond to certain questions. For the analyses I will be using the > results for, I need to estimate the missing data here. A poor-person's way > of doing it would be mean-substitution. > > Note that certain groups of people were not asked certain questions though > based on skip patterns. I cannot remove their column or row from the 200 X > 10 matrix and I still wish to figure what to do? > > Note that the scales are ordinal/continuous from 1 to 10. I made it so that > if they said Don't Know, the data becomes missing. I used zeroes to define > the cells where it is structurally missing and quite Kosher. Perhaps I > should use a character to make it explicit that it is not part of the scale > in the future. > > Any help on how to use Amelia with this kind of situation is greatly valued > and appreciated. Thank you. > > -- > Zachary S. Feinstein > Methodologist > Harris Interactive > zfeinstein(a)harrisinteractive.com > http://www.harrisinteractive.com > phone: (952) 541-7161 > > 435 Ford Road, Suite 250 > Minneapolis, MN 55426 > >

20 years, 9 months

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

Amelia July 2003