[Babase] ranking clarification needed

Karl O. Pinc kop at meme.com
Mon Sep 10 17:48:20 EDT 2007


On 09/10/2007 04:40:21 PM, Jun Yang wrote:
> On 9/2/07, Susan Alberts <alberts at duke.edu> wrote:
> 
> > 1. Given a month, a group, and a ranktype, there is just one
> ranking.
> >
> > Yes this is correct. In the RANKS table in babase, each "rank"
> refers to
> > exactly one month, group and ranktype.
> >
> > In particular, we never produce a ranking that "spans" multiple
> > months. This assumption is reflected by the current design of the
> > RANKS table.
> >
> 
> I thought I got this all cleared up, but here here is one more
> question.
> 
> RNKTYPES table uses a SQL query to define the set of individuals to
> rank for a given rank type. This definition takes three input
> parameters: group, start date, and end date. However, shouldn't the
> group of individuals be determined by the group and the month of the
> ranking alone? So why two dates? Should they always be the first and
> the last days of the month, respectively?
> 
> An alternative interpretation is that the RNKTYPE query gives the set
> of individuals to show in the interaction matrix of the ranker, which
> can be produced from an arbitrary date range (which can be long than
> the month being ranked). In that case, what happens when this set
> differs from the set of individuals to be included in the ranking?

Your alternative interpretation is the one that's used in practice.
The ambiguity you bring up regarding what happens when rankings are
saved is resolved by the expedient of never saving rankings unless
the matrix contains data for one and only one month.  This is
not enforced, other than by operator procedure.  (Partly because
they may someday want to save such rankings, and like any other
computer program user they'll hack up some convention that works and
only bother with changing the programs if it becomes too cumbersome.)

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



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