1. Overview of Connecticut Population Projections from 2015 to 2040
Weixing Zhang, Michael Howser, and Qinglin Hu
December, 2016

2. Background and Objective Input Data Methodology Future Work Reference
Outline
Background and Objective
Input Data
Methodology
Future Work
Reference

3. Background and Objective
Input Data
Methodology
References
What we have done
Population Projection of Connecticut State, County, Regional Planning Organizations, and Town from 2010 to 2025, with details of age and sex, based on the standard cohort-component projection.
Significance ranking
#1. Birth Projection
#2. Survival Projection
#3. Migration Projection
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
Total
Percent
Birth
42659
41996
42826
42005
41722
41789
41597
40388
38876
37715
411573
11.52%
Death
29817
30062
29527
29133
29264
29156
28563
28752
28394
28597
291265
8.15%
Residual of Birth and Death
12842
11934
13299
12872
12458
12633
13034
11636
10482
9118
120308
3.37%
Residual Net Migration
4822
48224
1.35%
Total Population

4. Background and Objective
Input Data
Methodology
References
Difficulty ranking
#1. Migration Projection
#2. Birth Projection
#3. Survival Projection
Objective
The purpose of this project is to incorporate multi-source datasets for producing population projections for each of the 169 towns in Connecticut from 2015 to 2040 by population projection method from UMass Donahue Institute, with details of age and sex.
Migration is the most difficult component to estimate and is the most likely source of uncertainty and error in population projections. Because there is not much we can do about birth projection and survival projection but holding fertility rate and survival rate constant over projection period. Fertility and mortality follow fairly regular age-related patterns.
However, the migration behavior of similar age groups is influenced by regional and national differences in socio-economic conditions. Furthermore, the data needed to estimate migration is often restricted or limited; especially for many small areas.
Migration includes Domestic Migration (In and Out migration), International Migration (immigration and emigration), College Migration. Whereas fertility and mortality follow fairly regular age-related patterns.

5. Background and Objective
Input Data
Methodology
References
Why use population projection method from UMass Donahue Institute?
#1. Similar demographic profile
#2. Similar migration behavior
Migration is the most difficult component to estimate and is the most likely source of uncertainty and error in population projections. Because there is not much we can do about birth projection and survival projection but holding fertility rate and survival rate constant over projection period. Because fertility and mortality follow fairly regular age-related patterns.
However, the migration behavior of similar age groups is influenced by regional and national differences in socio-economic conditions. Furthermore, the data needed to estimate migration is often restricted or limited; especially for many small areas.
Migration includes Domestic Migration (In and Out migration), International Migration (immigration and emigration), College Migration. Whereas fertility and mortality follow fairly regular age-related patterns.

6. Background and Objective
Input Data
Methodology
References
Why use population projection method from UMass Donahue Institute?
#1. Similar demographic profile
#2. Similar migration behavior
Migration is the most difficult component to estimate and is the most likely source of uncertainty and error in population projections. Because there is not much we can do about birth projection and survival projection but holding fertility rate and survival rate constant over projection period. Because fertility and mortality follow fairly regular age-related patterns.
However, the migration behavior of similar age groups is influenced by regional and national differences in socio-economic conditions. Furthermore, the data needed to estimate migration is often restricted or limited; especially for many small areas.
Migration includes Domestic Migration (In and Out migration), International Migration (immigration and emigration), College Migration. Whereas fertility and mortality follow fairly regular age-related patterns.

7. Background and Objective
Input Data
Methodology
References
Why use population projection method from UMass Donahue Institute?
#1. Similar demographic profile
#2. Similar migration behavior
Migration is the most difficult component to estimate and is the most likely source of uncertainty and error in population projections. Because there is not much we can do about birth projection and survival projection but holding fertility rate and survival rate constant over projection period. Because fertility and mortality follow fairly regular age-related patterns.
However, the migration behavior of similar age groups is influenced by regional and national differences in socio-economic conditions. Furthermore, the data needed to estimate migration is often restricted or limited; especially for many small areas.
Migration includes Domestic Migration (In and Out migration), International Migration (immigration and emigration), College Migration. Whereas fertility and mortality follow fairly regular age-related patterns.

8. Background and Objective
Input Data
Methodology
References
Before | Inputs
Base Population: 2010 Census
Birth
Death
Now | Inputs
Base Population: 2010 Census
Birth
Death
Migration
ACS PUMS
ACS 5 years estimate
PUMA level
Net-migration ratio method is either positive or negative. But in reality, net-migration can change over time.
Most analysts use a net migration approach, where a single net migration rate is calculated as the number of net new migrants per cohort (in-migrants minus out-migrants) divided by the baseline cohort population of the study region. Although common, the net migration approach suffers from several conceptual and empirical flaws. A major problem is that denominator of the net migration rate is based purely on the number of residents in the study region. However, none of the existing residents are at risk of migrating into the region – they already live there. While this may seem trivial, it has been shown to lead to erroneous and biased projections especially for fast growing and declining regions.
Town level

9. Background and Objective
Input Data
Methodology
References
Controlling town-level population projections to PUMA-level total projections that are based on a gross migration model (Renski, Koshgarian, and Strate, 2013)
Town Projection Population: 2015
PUMA Projection Population: 2015
Male
Male
Male
Male
( ) x W1 =
90 + +
90 + +
90 +
90 +
( ) x W2 =
85-89 +
85-89 +
85-89
85-89
( ) x W3 =
80-84 +
80-84 +
80-84
80-84
We will still use the standard cohort-component projection model from previous work since fertility and mortality follow fairly regular age-related patterns. We will focus on solving the dynamic changing “Migration” in PUMA level for final controlling.
Before this process, Population projection at PUMA was controlled by ACS population estimate at State level by adjusting in-migration or out-migration!!!!!!!!!!
( ) x W… =
15-19 +
15-19 +
15-19
15-19
( ) x W… =
10-14 +
10-14 +
10-14
10-14
( ) x W… =
5-9 +
5-9 +
5-9
5-9
( ) x W… =
0-4 +
0-4 +
0-4
0-4
North Haven
Wallingford
Meriden
PUMA:

10. Background and Objective
Input Data
Methodology
References
References
Renski, H., Koshgarian, L., & Strate, S. (2013). Long-term Population Projections for Massachusetts Regions and Municipalities. UMass Donahue Institute.
Connecticut State Data Center. (2012). Methodology for Population Projection of Connecticut State, County, Regional Planning Organizations, and Town from 2010 to 2025.
Connecticut State Department of Public Health & Connecticut State Data Center. (2016). Small area population estimates project summary report.

11. Questions? Website: In-person: Have questions? Email us at:
magic.lib.uconn.edu
ctsdc.uconn.edu
In-person:
Level 4 of the Homer Babbidge Library
Open 1-4 and by appointment
Have questions? us at: