[Babase] Statdate revisited -- Was: Re: Request for Susan's input on SCI5

Karl O. Pinc babase@www.eco.princeton.edu
Wed, 20 Jul 2005 18:36:15 +0000


Consensus here is that Leah should be responsible for
forwarding list traffic to Susan, so that needs to
be done for this message too.

On 07/20/2005 05:22:06 AM, Amboseli Baboon Research Project wrote:

> Yes we discussed this in the spring at our meeting, and I agree.  
> STATUS
> should be either alive or dead -- it is the status at the last  
> sighting of
> the animal. This is how it is now defined in the babase documentation  
> after
> recent edits.

> 
> Then STATUS
>> can be made to look like BSTATSUS, where there's codes for "alive",  
>> "dead,
>> date known exactly", "dead, within 1 week", "dead, within 1 month",  
>> etc.
>> Whatever time intervals make sense, not necessarily the same  
>> intervals
>> that are used in BSTATUS. KOP]
> 
> In principle this is OK, but I am not sure we need it because it is  
> the
> statdate that we care about not the death date. The statdate has no  
> error in
> it. In other words, I don't think in practice we would use this.

While Status _is_ the state of the animal on last sighting,
Statdate is _not_ the date of last sighting.  It is the
date of last sighting only when the individual is alive.
When the individual is dead, it's the death date and is
uncertain.  Of course everybody does not wind up dead,
(lucky them)
but for those who do you might need some uncertainty
indications.

(Obviously, the date of last sighting can be consistently
gotten, regardless of whether the indidivual's alive
or dead, from CENSUS.)

The idea here is that while the individual is alive,
statdate is a convenient way of determining the
interval over which data has been collected on the
individual. The Birth to Statdate interval, inclusive.  Likewise,
rather than have to query dead individuals differently
from live ones, Statdate records the date of death
and the Birth to Statdate interval remains the interval
over which data has been collected.

So, Status is really describing one of two different
things, the state of the animal when last seen
alive, and whatever elaboration on date of death
is required.  Because they never both occur at
the same time it all works out ok.

Note: My code is constantly looking to see if the
individual's is alive, by checking for a Status
of 0.  If we ever have more than one Status
code to mean "alive and kicking", in Babase
terms that means that the Statdate must be
the last CENSUS date (excepting absences),
some thought will have to go into it.

Karl <kop@meme.com>
Free Software:  "You don't pay back, you pay forward."
                  -- Robert A. Heinlein