NEISD Enrollment Projections: Methodology & Accuracy Prepared by Anthony A. Athens III August 11, 2008
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NEISD Enrollment Projections:Methodology & Accuracy
Prepared by Anthony A. Athens IIIAugust 11, 2008
Agenda
• Random Variations
• Short Range Projections
• Long-Range Projections
• Accuracy
• Triangulation
Annual Closings, Enrollment Growth, & Enrollment Growth Per
New Unit
500
2500
2000
1500
1000
2001 2002 200520042003 2006 *2008
2007
3000
0.79
0.750.61
0.38
0.63
0.50
0.38 0.52
Enro
llment
Gro
wth
* Projected
Clo
sings
My Summer Reading:Fooled By Randomness by Nassim
Taleb• Author is a former Wall Street trader
• The accuracy of predictions depends on:• Skills – Good & Poor• Luck – Good & Bad
• Acknowledging the role of luck (random unpredictable factors) helps avoid a false sense of confidence
Short-Range Projections• Cohort Model
• For next school year
• Projects enrollment for every grade at every campus
• Census Tract birth data from Metropolitan Health Department
• Historical survival rates calculated for every grade at every campus• Survival rates weighted to best capture recent trends
and discount anomalous data
Short-Range Projection Accuracy
0
10000
20000
30000
40000
50000
60000
70000
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 200793%
94%
95%
96%
97%
98%
99%
100%
Projected Actual Accuracy Average Accuracy
99.4%
Long-Range Projections• 180+ Neighborhood Projection Models
• Aggregated to Campus Level
• Cohort Model• Census Tract Birth Data from Metro. Health Dept.• Weighted Average Historical Survival Rates
• Housing Model• Enrollment Grows with Projected Housing• SA Research• Metrostudy• Other
• Constant Model
Long-Range Projection Accuracy: 1988 Bond
0
10000
20000
30000
40000
50000
60000
70000
80000
1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996
6.4%
Projected
Actual
Long-Range Projection Accuracy: 1995 Bond
0
10000
20000
30000
40000
50000
60000
70000
80000
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
10.4%
Projected
Actual
Long-Range Projection Accuracy: 1998 Bond
0
10000
20000
30000
40000
50000
60000
70000
80000
1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
3.9%
Projected
Actual
Long-Range Projection Accuracy: 2003 Bond
0
10000
20000
30000
40000
50000
60000
70000
80000
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
0.4%Projected
Actual
Long-Range Projection Accuracy: 2007 Bond
0
10000
20000
30000
40000
50000
60000
70000
80000
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
2.2%Projected
Actual
Long-Range Projections
0
10000
20000
30000
40000
50000
60000
70000
80000
Bond07Bond03Bond 98Bond95Bond88Actual
Triangulation
• Enrollment projections are periodically recalculated to better capture the latest enrollment and housing trends
• In addition to district-produced projections, outside contractors are hired to produce a second set of projection
Long-Range Projections: NEISD vs. Deskmap
0
10000
20000
30000
40000
50000
60000
70000
80000
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Deskmap
ActualNEISD
Questions
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