[Babase] MEMBERS Comparison - absent on birth

Catherine Markham babase@www.eco.princeton.edu
Fri, 30 Sep 2005 13:24:54 -0400


> This looks like a problem in the interpolation implimentation,
> not the rules.  If you could read over the rules and confirm that
> WEG really should not wind up in group 9 by the rules
> I'll fix up the program.  (I may have found a different
> problem too while adding and deleting the absence on
> 2005-02-02, but maybe it's the same problem....)
> 
> Thanks for finding this.
> 

Hi Karl,

I found the following sentences in the documentation regarding 
interpolation from birth:

"...An individual is placed in his Matgrp on his birth date even when a 
regular census has an absence recorded for the individual on the date of 
birth. In this case interpolation always entirely ignores the absence 
and will not use such an absence to compute a Halfway To Absence Interval."

So the new MEMBERS table worked correctly in placing WEG in his matgrp, 
2.20, on his birthday.  But it doesn't seem to have worked correctly 
with regard to group placement when interpolating from his birth to the 
next locating census.  Specifically, I don't understand the logic that 
would place WEG in Group 9 (both from the program standpoint and the 
biology standpoint).  It looks to me like it is using his absence in the 
matgrp to computer a Halfway to Absence Interval.

As a reminder, WEG's rows just after birth in the new MEMBERS table look 
like:

WEG 2005-02-02 2.20 I 0  (birth, absent on group census)
WEG 2005-02-03 9.00 I 1
WEG 2005-02-04 2.20 I 1
WEG 2005-02-05 2.20 C 0  (first present on group census)
WEG 2005-02-06 2.20 I 1

Again, for the record, all this isn't an issue with WEG anymore since we 
decided to change his birthdate.  The version of the new database online 
will still have the old data - my FoxPro version, the "working" copy of 
BaBase, has been corrected for Wegner.

Catherine