Framework for Phase 2 Modeling

Function of the Model: A platform for discussing alternative growth scenarios inMetro Boston and the associated tradeoffs

Five Study Areas: People and CommunitiesGetting AroundBuildings and LandscapesAir, Water and WildlifeProsperity

Phase 2: Baseline Model

• Narrative:

• Qualitative Narrative

• Quantitative Narrative

• Computer Model: Community

Viz

•15-25 Components

•7-15 Components

•3-6

•Components

Scenarios Agents

• Steering Committee

• Inter Issue Taskforce

• Technical and Content Liaison

• Consultant Team

• Public and Leadership Dialogues

Three Ways to Build Scenarios

• Inductive Approach-Data driven framework

• Deductive Approach- Start with framework and fill in data

• Incremental Approach- Start with “Official Future” fill in framework and data

Regional Population Projection

November 2005

MAPC

1990 Population by Cohort (Age, Sex, Race)

Future Natural Increase

Apply Migration Rates

Future Migration

Future Regional Population (Regional Control)

Death Rates Birth Rates

Trend of Municipal Share by Age

Trend of Municipal Total Share

Future Municipal Population by Age

2000 Population by Cohort

Difference = Migration by Cohort

Future Municipal Total Population

Regional Population Projection

Municipal PopulationLocation

BaseYear

Population

ProjectedYear

Population

Birth

Survival

Migration

Cohort-Component Method

MAPCAugust 10, 2005

BaseYear

Population

ProjectedYear

Population

Birth

Survival

Migration

Cohort-Component Method

ChildBearingCohorts

EveryCohort

Survived& Aged

Population

NewBirths

NetRemainingPopulation

Birth Rate

Survival Rate

Net Migration Rate

=

MAPCAugust 10, 2005

How to estimate the rates?

Survival Rate and Aging

• Age-sex-race specific survival rate• As of year 2000

PopulationofNumber

DeathsofNumberRateSurvival 1

PopulationCohortRateSurvivalPopulationAging

1990 Population by Cohort (Age, Sex, Race)

Future Natural Increase

Apply Migration Rates

Future Migration

Future Regional Population (Regional Control)

Death Rates Birth Rates

Trend of Municipal Share by Age

Trend of Municipal Total Share

Future Municipal Population by Age

2000 Population by Cohort

Difference = Migration by Cohort

Future Municipal Total Population

Regional Population Projection

Municipal PopulationLocation

How to estimate the trend of the share of each community

Logarithmic CurveTrend of Share

y = -0.0973Ln(x) + 1.3857

R2 = 0.8468

y = 0.0084Ln(x) + 0.3161

R2 = 0.7785

0.31

0.315

0.32

0.325

0.33

0.335

0.34

0.345

0.35

0 5 10 15 20 25 30 35

Year (1970=1; 2000=31; 2030=61)

Pe

rce

nt

Sh

are

0.7

0.8

0.9

1

1.1

1.2

1.3

1.4

1.5

Abington Arlington Log. (Arlington) Log. (Abington)

Left Axis - Abington

Right Axis - Arlington

Calibration

Calibration based on Year 2000

Trend of Share

y = -0.0973Ln(x) + 1.3857

R2 = 0.8468

y = 0.0084Ln(x) + 0.3161

R2 = 0.7785

0.31

0.315

0.32

0.325

0.33

0.335

0.34

0.345

0.35

0 5 10 15 20 25 30 35

Year (1970=1; 2000=31; 2030=61)

Pe

rce

nt

Sh

are

0.7

0.8

0.9

1

1.1

1.2

1.3

1.4

1.5

Abington Arlington Log. (Arlington) Log. (Abington)

Left Axis - Abington

Right Axis - Arlington

* Calibration shifts up or down the line to pass through the data of year 2000.

Regional Employment Projection

MAPC

National Employment Total

Regional Employment Total

Regional Employment By Sector

Trend of Regional Total Share

Trend of Municipal Sectoral Share

Municipal Employment By Sector

Trend of Municipal Total Share

Trend of Regional Sector Share

Total Municipal Employment

Regional Employment Projection

Municipal Employment Location

EMP

LOGX

3020100

140000000

130000000

120000000

110000000

100000000

90000000

80000000

70000000

Observed

Logarithmic

National Total Employment 1982-2004

Shift-Share & Two-way Sectoral Projection

EA_AG_PR

LOGX

1614121086420

.021

.020

.019

.018

Observed

Logarithmic

Regional Share of National Employment 1990-2004

Shift-Share & Two-way Sectoral Projection

Regional Employment Total

RegionalEmployment

Total

NationalEmployment

Total

Regional Share

Shift-Share & Two-way Sectoral Projection

National Structural Change 1982-2004

N_SSPROR

LOGX

3020100

.22

.20

.18

.16

.14

.12

.10

Observed

Logarithmic

N_SSPROR

LOGX

3020100

.13

.12

.11

.10

.09

.08

.07

Observed

Logarithmic

Manufacturing(Down: 20 % to 12 %)

Professional Service(Up: 8.5 % to 12 %)

N_SSPROR

LOGX

3020100

.13

.12

.11

.10

.09

.08

.07

Observed

Logarithmic

N_SSPROR

LOGX

3020100

.18

.17

.16

.15

Observed

Logarithmic

Government(Down: 18 % to 16 %)

Education & Health(Up: 8 % to 12 %)

Shift-Share & Two-way Sectoral Projection

Regional Variation of Structure 1990-2004

EAVARIAT

LOGX

1614121086420

0.000

-.002

-.004

-.006

-.008

-.010

-.012

-.014

-.016

Observed

Logarithmic

EAVARIAT

LOGX

1614121086420

.040

.038

.036

.034

.032

.030

.028

.026

.024

Observed

Logarithmic

EAVARIAT

LOGX

1614121086420

.07

.06

.05

.04

Observed

Logarithmic

EAVARIAT

LOGX

1614121086420

-.039

-.040

-.041

-.042

-.043

-.044

-.045

Observed

Logarithmic

Manufacturing(Down: -0.2 % to -1.4 %)

Professional Service(Up: 2.6 % to 3.4 %)

Government(Down: -4 % to -4.2 %)

Education & Health(Down: -6 % to -5 %)

Shift-Share & Two-way Sectoral Projection

National Employment Total

Regional Employment Total

Regional Employment By Sector

Trend of Regional Total Share

Trend of Municipal Sectoral Share

Municipal Employment By Sector

Trend of Municipal Total Share

Trend of Regional Sector Share

Total Municipal Employment

Regional Employment Projection

Municipal Employment Location

Land Use ModelAllocation to Traffic Analysis Zones

November 2005

MAPC

Land Use ModelAllocation to Traffic Analysis Zones

Population/Housing Units

• Three components of Housing Unit Growth– Greenfield Development – Densification– Community Comments

• Housing unit estimates are scaled to meet the projected housing unit demand, based on population and household size.

Greenfield Development• Rate of new residential land is based on land

consumption rate from 1971-1999.• Buildable land excludes permanently protected

open space, wetlands, commercial/industrial zones, and built land.

• Housing development occurs at the density allowed by underlying zoning, with a 10% discount for roads and unbuildable areas.

• Not more than 80% of remaining buildable units can be constructed in any one decade.

Land Use ModelHousing Unit Development

Densification• “Densification Factor” calculated for each

community, based on increase in housing units per acre of developed land, 1970-2000.

• Multiplied by the square of the Buildout Factor so that densification is focused in those TAZs that are closer to buildout.

• Multiplied by the amount of developed land to yield number of densification units.

Land Use ModelHousing Unit Development

Community Comments • Some community comments indicated specific

numbers of units for specific TAZs. • Where a range was given, MAPC usually used

the low end of the range and paced multi-decade developments conservatively.

• If specific numbers of units were not indicated, substituted 5% of total housing unit demand.

Land Use ModelHousing Unit Development

Scaling • Preliminary housing unit projections (Greenfield

and Densification) were summed across all TAZs in community.

• Community Comment units not subject to scaling. • (Total HU demand – community comment units) ÷

preliminary housing unit projections = scale factor. • Scale factor applied to preliminary HU projections

for each TAZ; add community comment units to yield Adjusted Total Housing Units.

• Adjusted Total Housing Units assumed to have the same Greenfield-Densification proportions as Preliminary HU projections.

Land Use ModelHousing Unit Development

Land Use ModelHousing Unit Development

60%

40%

Community Comment

Units

Densification Units

Greenfield Units

Housing Unit

Demand“Preliminary Housing Units"

60%

40%

Adjusted Housing

Unit Total

Land Use ModelEconomic Development

TAZ-level Employment Projections• Rate of new commercial/industrial/urban open land

is based on land conversion rate 1985-1999.• Buildable land excludes wetlands, protected open

space, residential zones, built areas. Discounted by 10% to allow for roads and unbuildable areas.

• Job Densification factor: increase in employees per acre of commercial/industrial/urban open land per decade.

• Initial total employment is a function of Total C/I/UO land times new Job Density.

Land Use ModelEconomic Development

Sectoral Allocations• Initial total employment is multiplied by previous

decade’s sectoral proportions to yield initial sectoral employment.

• Initial sectoral employment summed across all TAZ’s and compared to projected community-level sectoral employment to yield a scale factor.

• Initial sectoral employment scaled accordingly. • Adjusted employment for all sectors summed to

yield adjusted total employment for TAZ.

Community Viz Model Schematic