[R] Creating NA equivalent

[Jim Lemon]

Hi Bert,
What troubles me about this is that something like detectable level(s)
is determined at a particular time and may change. Censoring in
survival tells us that the case lasted "at least this long". While a
less than detectable value doesn't give any useful information apart
from perhaps "non-zero", an over limit value gives something like
censoring with "at least this much". However, it is more difficult to
conceptualize and I suspect, to quantify. To me, the important
information is that we think there _may be_ a value but we don't
(yet?) know it.

Jim

On Wed, Dec 22, 2021 at 9:56 AM Bert Gunter <bgunter.4567 using gmail.com> wrote:
>
> But you appear to be missing something, Jim -- see inline below (and
> the original post):
>
> Bert
>
>
> On Tue, Dec 21, 2021 at 2:00 PM Jim Lemon <drjimlemon using gmail.com> wrote:
> >
> > Please pardon a comment that may be off-target as well as off-topic.
> > This appears similar to a number of things like fuzzy logic, where an
> > instance can take incompatible truth values.
> >
> > It is known that an instance may have an attribute with a numeric
> > value, but that value cannot be determined.
> Yes, but **something** about the value is known: that it is > an upper
> value or < a lower value. Such information should be used
> (censoring!), not characterized as completely unknown. Think about it
> in terms of survival time: saying that a person lasted longer than k
> months is much more informative than saying that how long they lasted
> is completely unknown!
>
> >
> > It seems to me that an appropriate designation for the value is Unk,
> > perhaps with an associated probability of determination to distinguish
> > it from NA (it is definitely not known).
> >
> > Jim
> >
> > On Wed, Dec 22, 2021 at 6:55 AM Avi Gross via R-help
> > <r-help using r-project.org> wrote:
> > >
> > > I wonder if the package Adrian Dușa created might be helpful or point you along the way.
> > >
> > > It was eventually named "declared"
> > >
> > > https://cran.r-project.org/web/packages/declared/index.html
> > >
> > > With a vignette here:
> > >
> > > https://cran.r-project.org/web/packages/declared/vignettes/declared.pdf
> > >
> > > I do not know if it would easily satisfy your needs but it may be a step along the way. A package called Haven was part of the motivation and Adrian wanted a way to import data from external sources that had more than one category of NA that sounds a bit like what you want. His functions should allow the creation of such data within R, as well. I am including him in this email if you want to contact him or he has something to say.
> > >
> > >
> > > -----Original Message-----
> > > From: R-help <r-help-bounces using r-project.org> On Behalf Of Duncan Murdoch
> > > Sent: Tuesday, December 21, 2021 5:26 AM
> > > To: Marc Girondot <marc_grt using yahoo.fr>; r-help using r-project.org
> > > Subject: Re: [R] Creating NA equivalent
> > >
> > > On 20/12/2021 11:41 p.m., Marc Girondot via R-help wrote:
> > > > Dear members,
> > > >
> > > > I work about dosage and some values are bellow the detection limit. I
> > > > would like create new "numbers" like LDL (to represent lower than
> > > > detection limit) and UDL (upper the detection limit) that behave like
> > > > NA, with the possibility to test them using for example is.LDL() or
> > > > is.UDL().
> > > >
> > > > Note that NA is not the same than LDL or UDL: NA represent missing data.
> > > > Here the data is available as LDL or UDL.
> > > >
> > > > NA is built in R language very deep... any option to create new
> > > > version of NA-equivalent ?
> > > >
> > >
> > > There was a discussion of this back in May.  Here's a link to one approach that I suggested:
> > >
> > >    https://stat.ethz.ch/pipermail/r-devel/2021-May/080776.html
> > >
> > > Read the followup messages, I made at least one suggested improvement.
> > > I don't know if anyone has packaged this, but there's a later version of the code here:
> > >
> > >    https://stackoverflow.com/a/69179441/2554330
> > >
> > > Duncan Murdoch
> > >
> > > ______________________________________________
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> >
> > ______________________________________________
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