Forum Reader Wrote:
-------------------------------------------------------
> Anonymous Wrote:
> > ... People moved from Hayfield to South County
> because
> > they thought the process was valid and the
> > projections were accurate and there wouldn't be
> > overcrowding at South County in spite of the
> > community having accurate numbers.
> >
> > Nobody except Forum Reader believes FCPS
> > projections anymore
> >
> ------------
> Process and projections had little to do with it;
> they knew SCSS would be crowded if the lines were
> drawn the way they are but everyone wanted to go
> to the new school. People who fought hard to have
> SCSS built did not want to stay in Hayfield. The
> School Board did not have the courage to say "no"
> to more of them. Look at the Lorton area, the
> locations of SCSS and Hayfield, and the roads, AND
> look at Fort Belvoir and the limited access
> through it and you might sympathize with these
> families.
>
> FCPS projections are not perfect, but no one has
> presented any better. If you have some, with web
> site and source, I'd be happy to look at them.
FR-
Sorry I never did get back to you. Use the raw data here:
http://www.fcps.edu/Reporting/
Go by cohorts and adjust starting with an adjustment using the 5 year average of inflows or outflows. This is the standard FCPS model for projections. Once you understand the model FCPS uses and backtest for errors you can see the problems and adjust.
To your point, it started with the politics as it always does, then it contaminated the process and then from there the projections were adjusted to fit the desired result. So all three played a role and at the time people were naive to the role of the politics. Many people had numbers more accurate than FCPS projections which is why they were forced to have a projection task force.
Since you are adept with the CIP go back say 2 years and see where schools were projected to be today and where they actually are now. McKibben recommends a 2% per year error variance.