[Babase] "On" vs "By" sexual maturity dates & Tdate maturity markers

Jeanne Altmann babase@www.eco.princeton.edu
Thu, 27 Oct 2005 13:21:37 -0400


At 01:11 PM 27/10/2005, you wrote:
>>Susan, maybe you could answer this.  If not would
>>you please draw Jeanne's attention?
>
>
>I called Jeanne and told her to read this.
>
>>
>>I assume that when female's have a "By" date then their
>>first Tdate need not be their assigned maturity date, it could
>>be sometime after.  Right?
>
>
>This is correct according to my understanding.

YES, THE FIRST T MAY BE AFTER THE 'BY' MATDATE


>>This plays into Jeanne's comments on the documentation
>>where she seems to assume that maturity dates will
>>have some sort of Bstatus like plus-or-minus X years
>>time range.   If I'm reading her comments right.
>>I don't think we want this.
>
>
>My understanding is that mature dates will be definite. They will either 
>be ON or they will be BY. We will only use the ON to estimate age at 
>attainment. We can use both ON and BY to identify age sex classes at any 
>given time.
>
>There is a question of how we deal with the fact that some ON dates have 
>larger margins of error than others. I think that we have a large enough 
>sample of these for now that we can afford to be picky and only use dates 
>that have a narrow margin of error. This would mean that all dates that 
>now have an E attached to them (for estimated) in the current (FoxPro) 
>version of babase would become BY dates and would never be used to 
>estimate age at attainment of the marker in question.

YES, AGREED; I WAS NOT ADEQUATELY THINKING ABOUT THE NEW 'BY' SYSTEM


>>I seem to recall arriving at the conclusion that all
>>maturity dates are definite -- even though some
>>simply set a definite upper bound.  This sounds
>>good.  And it seems ok that those that are not
>>exact need not be exactly on a Tdate.
>
>
>This agrees with my understanding.

AGREED


>>If it turns out we do want some rough estimate of
>>when maturity happened I'd say that's a different
>>bit of data and we should leave the current
>>maturity date design alone and add to it to
>>get more information.  A phone call would be
>>required I think.
>
>OK. I am inclined to leave the option open at the moment. In other words I 
>don't see a strong need to build it into the system right now, given that 
>we can do so later if we want to. Jeanne?

AGREED
JEANNE

>Susan
>
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>
>--
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>Susan Alberts, Associate Professor Department of Biology, Duke University, 
>Box 90338, Durham NC 27708 phone 919-660-7272  fax 919-660-7293
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