R devel - May 2021 - 1954 from NA

Adrian,
> If it was only one column then your solution is neat. But with 5-600
> variables, each of which can contain multiple missing values, to
> double this number of variables just to describe NA values seems to me
> excessive.  Not to mention we should be able to quickly convert /
> import / export from one software package to another. This would imply
> maintaining some sort of metadata reference of which explanatory
> additional factor describes which original variable.
one thing *i* should keep in mind is the old saying: "The difference
between theory and practice is that in theory there is no difference,
but in practice, there is."

but, in theory:

if you have 500 columns of possibly-NA'd variables, you could have one
column of 500 "bits", where each bit has one of N values, N being the
number of explanations the corresponding column has for why the NA
exists.

i guess the CS'y thing that comes to my mind here is that one thing is
the *semantics* of what you are trying to convey, and the other is how
those semantics are *encoded* in whatever representation you are using.

cheers, Greg

On Mon, May 24, 2021 at 2:11 PM Greg Minshall <minshall at umich.edu>
wrote:
> [...]
> if you have 500 columns of possibly-NA'd variables, you could have one
> column of 500 "bits", where each bit has one of N values, N being
the
> number of explanations the corresponding column has for why the NA
> exists.
>
The mere thought of implementing something like that gives me shivers. Not
to mention such a solution should also be robust when subsetting,
splitting, column and row binding, etc. and everything can be lost if the
user deletes that particular column without realising its importance.

Social science datasets are much more alive and complex than one might
first think: there are multi-wave studies with tens of countries, and
aggregating such data is already a complex process to add even more
complexity on top of that.

As undocumented as they may be, or even subject to change, I think the R
internals are much more reliable that this.

Best wishes,
Adrian

-- 
Adrian Dusa
University of Bucharest
Romanian Social Data Archive
Soseaua Panduri nr. 90-92
050663 Bucharest sector 5
Romania
https://adriandusa.eu

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