Re: [R] Survey Design / Rake questions

[Thomas Lumley]

On Mon, 25 Aug 2008, Farley, Robert wrote:

I see a number of things that bother me.
 1) str(ByEBNum$StnTraveld) says "int [1:12] 1 2 3 4 5 6 7 8 9 10 ..."
        Even though "StnTraveld  <- c(as.factor(1:12))"

You don't want the c()
a<-as.factor(1:12)
str(a)
 Factor w/ 12 levels "1","2","3","4",..: 1 2 3 4 5 6 7 8 9 10 ...
str(c(a))
 int [1:12] 1 2 3 4 5 6 7 8 9 10 ...

As the help for c() says  "all attributes except names are removed.", 
which includes the factor levels.

 2) ByEBOn$StnName[1:5] seems to imply I have extra spaces in the data.  Where 
would they have come from?

No, that's just R printing things in columns
a<-factor(1:12, labels=c(1:11,"antidisestablishmentarianism"))
a
 [1] 1                            2
 [3] 3                            4
 [5] 5                            6
 [7] 7                            8
 [9] 9                            10
[11] 11                           antidisestablishmentarianism
Levels: 1 2 3 4 5 6 7 8 9 10 11 antidisestablishmentarianism


 3) I'd like to verify that the order (value) of "EBSurvey$lineon" 
matches my definition in "StnName"

all(levels(EBSurvey$lineon)==StnName)

        -thomas


Thanks for helping...


***************************************************************************
***************************************************************************
library(survey)
SurveyData <- read.spss("C:/Data/R/orange_delivery.sav", use.value.labels=TRUE, 
max.value.labels=Inf, to.data.frame=TRUE)
#===============================================================================
temp <- sub(' +$', '', SurveyData$direction_)
SurveyData$direction_ <- temp
#===============================================================================
SurveyData$NumStn=abs(as.numeric(SurveyData$lineon)-as.numeric(SurveyData$lineoff))
mean(SurveyData$NumStn)
[1] 6.785276
### Kludge
SurveyData$NumStn <- pmax(1,SurveyData$NumStn)
mean(SurveyData$NumStn)
[1] 6.789877
SurveyData$NumStn <- as.factor(SurveyData$NumStn)
###
EBSurvey <- subset(SurveyData, direction_ == "EASTBOUND" )
XTTable <- xtabs(~direction_ , EBSurvey)
XTTable
direction_
EASTBOUND
     345
WBSurvey <- subset(SurveyData, direction_ == "WESTBOUND" )
XTTable <- xtabs(~direction_ , WBSurvey)
XTTable
direction_
WESTBOUND
     307
#
EBDesign <- svydesign(id=~sampn, weights=~expwgt, data=EBSurvey)
#   svytable(~lineon+lineoff, EBDesign)
StnName     <- c( "Warner Center", "De Soto", "Pierce College", "Tampa", "Reseda", "Balboa", "Woodley", "Sepulveda", "Van 
Nuys", "Woodman", "Valley College", "Laurel Canyon", "North Hollywood")
EBOnNewTots <- c(            1000,       600,             1200,     500,     
1000,      500,       200,         250,       1000,       300,              100,   
       123.65,                0 )
StnTraveld  <- c(as.factor(1:12))
EBNumStn    <- c(673.65,     800, 1000, 1000,  800,  700,  600, 500, 400, 200,  
50, 50 )
ByEBOn  <- data.frame(StnName,   Freq=EBOnNewTots)
ByEBNum <- data.frame(StnTraveld, Freq=EBNumStn)
RakedEBSurvey <- rake(EBDesign, list(~lineon, ~NumStn), list(ByEBOn, ByEBNum) )
Error in postStratify.survey.design(design, strata[[i]], 
population.margins[[i]],  :
 Stratifying variables don't match

str(EBSurvey$lineon)
Factor w/ 13 levels "Warner Center",..: 3 1 1 1 2 13 1 5 1 5 ...
EBSurvey$lineon[1:5]
[1] Pierce College Warner Center  Warner Center  Warner Center  De Soto
13 Levels: Warner Center De Soto Pierce College Tampa Reseda Balboa ... North 
Hollywood
str(ByEBOn$StnName)
Factor w/ 13 levels "Balboa","De Soto",..: 11 2 5 8 6 1 12 7 10 13 ...
ByEBOn$StnName[1:5]
[1] Warner Center  De Soto        Pierce College Tampa          Reseda
13 Levels: Balboa De Soto Laurel Canyon North Hollywood ... Woodman

str(EBSurvey$NumStn)
Factor w/ 12 levels "1","2","3","4",..: 10 12 4 12 8 1 8 8 12 4 ...
EBSurvey$NumStn[1:5]
[1] 10 12 4  12 8
Levels: 1 2 3 4 5 6 7 8 9 10 11 12
str(ByEBNum$StnTraveld)
int [1:12] 1 2 3 4 5 6 7 8 9 10 ...
ByEBNum$StnTraveld[1:5]
[1] 1 2 3 4 5

********************************************************************************************************************************************************

Robert Farley
Metro
www.Metro.net


-----Original Message-----
From: Thomas Lumley [mailto:[EMAIL PROTECTED]
Sent: Saturday, August 23, 2008 09:38
To: Farley, Robert
Cc: r-help@r-project.org
Subject: Re: [R] Survey Design / Rake questions

On Fri, 22 Aug 2008, Farley, Robert wrote:

I *think* I'm making progress, but I'm still failing at the same step.  My rake 
call fails with:
Error in postStratify.survey.design(design, strata[[i]], 
population.margins[[i]],  :
 Stratifying variables don't match

To my naïve eyes, it seems that my factors are "in the wrong order".  If so,
how do I "assert" an ordering in my survey dataframe, or copy an "image" from
the survey dataframe to my marginals dataframes?  I'd prefer to "pull" the
original marginals dataframe(s) from the survey dataframe so that I can
automate that in production.

It looks like a problem with the NumStn factor. One copy has been converted to 
character and then factor, giving levels in alphabetical order; the other copy 
has been converted directly to factor, giving levels in numerical order.

If you use as.factor(1:12) rather than as.character(1:12) it should work.

     -thomas



If that's not my problem, where might I look for enlightenment?  Neither "?why" 
nor ?whatamimissing return citations.  :-)


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Thomas Lumley                   Assoc. Professor, Biostatistics
[EMAIL PROTECTED]       University of Washington, Seattle______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.