[Babase] mstatus E
Susan Alberts
babase@www.eco.princeton.edu
Fri, 9 Apr 2004 14:03:44 -0400
>Hi everyone,
>
>I've been pulling togather some data for Jeanne on male ages at
>maturation, and we came across an issue with the use of "E" for
>Mstatus. In the protocol, an "E" in Mstatus is defined as an estimated
>matured date that is 4.5 years from birth for females and 5.5 years from
>birth for males (earlier for Lodge). But I looked at several males with
>Mstatus of "E", and their matured dates were not 5.5 years from birth,
>so I did some investigating. Most of the matured dates were in fact
>estimated, but because they were interpolated when data was missing.
>Some were estimated because only a few months were missing. Some were
>estimated because a whole year was missing, or there was extremely
>little information.
>
>So this means that "E" currently includes two different types of
>estimation. Obviously, to get calculate ages at maturation, we want to
>use individuals with known, not estimated, birth and matured dates, and
>we want to be able to distinguish between known and estimated in
>Biograph. So Jeanne's thinking was that we should keep Es for both
>types of estimation, and change to definition of E to include both
>types.
I have been thinking about this too.
I think that we probably should only have data in the matured column
that we think w might actually want to use in an analysis of age at
maturation. So, I think that we should NOT have E when a whole year
is missing, and should not have any maturation date at all in that
case. I can't imagine that having such a date would ever be useful to
us, and we run too much risk of confusion. I can imagine using data
estimated to within a few months, so it is probably OK to keep
maturation data, with an E, in that case.
One might argue that having estimated matured dates helps to figure
out who is subadult as of when, etc. But I think we should approach
this by having a "subadult by" and "adult by" table.
>
>Currently, we have been interpolating when a few months of maturation
>data are missing without using an E. So the Es when just a few months
>were missing are inconsistent with what we're doing now.
These 2 sentences confused me -- was there a mistake in them? Can you
re-explain?
>Jeanne and I
>thought that these cases should NOT have Es.
Hhmm -- sorry, I am still confused. Sorry to be slow on this.
>But we need to decide a
>cut-off point between what doesn't get an E and what does. Jeanne
>thought something like 4 or more months of missing data.
>
>This issue with "E" came up when Karen and I were looking at the matured
>dates of females for a question of Karl's. We came across a couple of
>cases where the matured dates were estimated by interpolation when there
>was a gap in the data, and we decided NOT to enter Es in these cases so
>that we didn't have Es in Biograph meaning two different things. (See
>emails re: female matured dates on 5 & 6 Feb.) But now I see the value
>of having E mean both types of estimation, so that we can distinguish
>between known and estimated. So if we decide to keep Es for
>interpolation estimating, I'll have to put the ones for those females in
>too.
>
>Thoughts?
>Daphne
>
>
>
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--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Susan Alberts, Assistant Professor
Department of Biology, Duke University, Box 90338, Durham NC 27708
phone 919-660-7272 fax 919-660-7293