The -ipf- command (not function) is written by Adrian Mander, who I
think is only intermittently a member of this list.
It was written up in STB-55. Have you read that account, accessible at
<http://www.stata.com/products/stb/journals/stb55.pdf>
I'd expect -ipf- to expect an observation on each person, coded
according to their category on each of several categorical variables,
but I've never tried it.
If this doesn't help, I suggest you contact the program author directly.
Nick
[email protected]
[email protected]
I apparently don't have my data in a form that allows stata v 10.1 to
run the ipf function.
I have a dataset of 262 observations coded by 6 variables, all
categorical and all, hypothetically, independent.
varlist is
genre
race
type
condition
fda_cat
page_size
I ran a multiple correspondence analysis (using XLStat) to look at
patterns with and without the binary variable (race). It was
recommended that I should also run log-linear models on the data.
What form does the data need to be in for stata to perform the ipf
command? I have tried several forms:
1. full spreadsheet data of 262 observations, each observation coded
with string variables. Six variables of interest, range from
dichotomous choices, three choices, or five choices. None are
ordinal. All categorical.
describe
Contains data
obs: 262
vars: 6
size: 14,410 (99.9% of memory free)
------------------------------------------------------------------------
---------
storage display value
variable name type format label variable label
------------------------------------------------------------------------
---------
genre str3 %9s
race byte %8.0g
type str7 %9s
condition str28 %28s
fda_cat str4 %9s
page_size str4 %9s
2. multiway contingency (freq) table, where freq counts of 262
observations were combined into like combinations showing 63 similar
observations (rows). The frequencies (cell counts) for each of the 63
rows ranged from 1 to 35.
Contains data from C:\Documents and Settings\LaVera
Crawley\Desktop\transformed
> log linear data.dta
obs: 63
vars: 7 14 Aug 2008 20:52
size: 1,008 (99.9% of memory free)
------------------------------------------------------------------------
-------
storage display value
variable name type format label variable label
------------------------------------------------------------------------
-------
genre byte %8.0g
race byte %8.0g
type byte %8.0g
condition byte %8.0g
fda_cat byte %8.0g
page_size byte %8.0g
freq int %8.0g
------------------------------------------
Neither form of the data worked. I still get the error r(109) type
mismatch message as below (despite what linear equation I use - with
or without interaction terms):
For example:
. ipf [fw=freq], fit( race+ genre+ type+ condition+ fda_cat+ page_size)
Deleting all matrices......
Expansion of the various marginal models
----------------------------------------
marginal model 1 varlist : race
marginal model 2 varlist : genre
marginal model 3 varlist : type
marginal model 4 varlist : condition
marginal model 5 varlist : fda_cat
marginal model 6 varlist : page_size
unique varlist race genre type condition fda_cat page_size
invalid syntax
r(198);
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