# Presentation: 921876

## Census Bureau’s Interim and Final State Projections

**Population Projections Branch**
**Population Division**
**U.S. Census Bureau**

- U.S. Census Bureau

## Interim State Population Projections  2004 - 2030

- U.S. Census Bureau

## Introduction

**Rationale for interim population projections**
**Section outline **
**Methodology**
**Assumptions**
**Proposed products**

- U.S. Census Bureau

## Methodology

**Cohort Component Method**
**Project Births, Deaths, Internal Migration, and International Migration separately**
**Basic Formula:**
**P****1**** = P****0**** + B - D + IIM - IOM + NIM**
**Where,**
**	****P****0  ****= Base year population**
**	****B = Projected births **
**	****D =  Projected deaths **
**	****IIM = Projected internal in-migration **
**	****IOM = Projected internal out-migration **
**	****NIM = Projected net international migration**

- U.S. Census Bureau

**Notes:**
The preparation of input data also depends on the methodology.

## Assumptions

**Fertility: **
**Fertility rates held constant, with adjustment to fit estimated births from 2001 to 2003**
**Mortality:**
**Mortality rates held constant, with adjustment to fit estimated deaths from 2001 to 2003**
**Internal migration:**
**Follow the IRS migration trends in region-to-state and state-to-region migration flows.**
**Hold the composition of 1995-2000 census migration flows constant.**
**International migration:**
**Follow the current international trends in states**
**Hold constant the composition of 1995-2000 immigrant population in the state**

- U.S. Census Bureau

**Notes:**
The input data needed also depend on the assumptions we made.

## Proposed Products

**Highlights (Press release)**
**Summary tables with statistics such as median age, sex ratio, dependency ratio and graphs such as pyramids  **
**Detailed age, and sex for all states, year by year (2004-2030)**

- U.S. Census Bureau

## Slide 7

- U.S. Census Bureau

## Final State Population Projections  2005 - 2030

- U.S. Census Bureau

## Introduction

**Challenges to new projections **
**Data consistency issues between Census 2000 and  previous censuses**
**Data consistency issues between census data and other data sources such as NCHS**
**Section outline **
**Methodology**
**Input data**
**Assumptions**
**Proposed products**

- U.S. Census Bureau

## Methodology

**Cohort Component Method**
**Project Births, Deaths, Internal Migration, and International Migration separately**
**Basic Formula:**
**P****1**** = P****0**** + B - D + IIM - IOM + NIM**
**Where,**
**	****P****0  ****= Base year population**
**	****B = Projected births **
**	****D =  Projected deaths **
**	****IIM = Projected internal in-migration **
**	****IOM = Projected internal out-migration **
**	****NIM = Projected net international migration**

- U.S. Census Bureau

**Notes:**
The preparation of input data also depends on the methodology.

## Methodology

**To project the demographic details, the formula should be expanded as follows:**
**1**** P****i,j,k ****= ****0**** P****(i-1),j,k**** + B****j,k**** - D****i,j,k**** + IIM****i,j,k**** - IOM****i,j,k**** + NIM****i,j,k**
**Where,**
**	****i = age ( 0 - 85 and over)**
**	****j = sex (male, female)**
**	****k = race/Hispanic origin (White, Black, American Indian, Asian, Hawaiian, and  multi-race by Hispanic origin, a total of 12 groups)**

- U.S. Census Bureau

**Notes:**
Since we need to project the population by age, sex, race. And Hispanic origin, the original formula should be expanded.
Each component can be treated as a multi-level matrix in the spreadsheet, one by one as seen in the following slide.

## Input Data

**Starting point: **
**Census 2000 for base year and denominator of rates**
**Births 1999, 2000, 2001 for fertility rates**
**Deaths 1999, 2000, 2001 for mortality rates**
**Internal migration:**
** ****IRS annual migration flows data: 1975 -2003 **
**Census migration flows data: 1995-2000**
**Foreign born population entering U.S. : 1995 - 2000**
**Population estimates and component of change: 2001 to 2004**
**Age, sex, race, and Hispanic origin for all data items except IRS****	**

- U.S. Census Bureau

## Input Data

**Projection years:**
**Projected national fertility rates**
**Projected national survival rates**
**Projected IRS region-to-state and state-to-region migration rates**
**Projected national population**
**Projected national births**
**Projected national deaths**
**Projected national international migration**
**Change in state fertility rates: 1990-2000**
**Change in state survival rates: 1990-2000**

- U.S. Census Bureau

**Notes:**
Besides IRS migration flows data, all the input data matrix by age, sex, race, and Hispanic origin can be tabulated in the spreadsheet.

To manipulate the data in spreadsheet along with graphic presentation allows us to evalulate the data more closely in identifying problems or issues.

Let’s look at the input data for each component.

## Base Population

**Use modified Census 2000 race data (31 race combinations)**
- The “some other race group” was eliminated
_**[http://eire.census.gov/popest/data/national/tables/files/MR(31)-CO.txt](http://eire.census.gov/popest/data/national/tables/files/MR(31)-CO.txt)**_
**	****	****	****	****	**
**Tabulate “Minimum and Maximum” race groups**
**Convert Census 2000 race groups to 1990 race groups, using equal fraction assignment procedure**
**State population estimates 2004**

- U.S. Census Bureau

**Notes:**
The base population is very critical to population projections, first it determine the starting point of population base for developing fertility rates, mortality rates, and migration rates.
For bridging the race groups:
Import the data, assign the race codes and fractions, and then calculate using SUMIF function.

## Fertility Input Data

**Births by age and race of mother from NCHS: **
**1989, 1990, 1991, 1999, 2000, and 2001 **
**Bridged census 2000 female 15-49 by race**
**Age-specific fertility rates based on 1990 race only for 6 race groups**
**(1) Non-Hispanic total**
**(2) Non-Hispanic white **
**(3) Non-Hispanic black **
**(4) Non-Hispanic American Indian **
**(5) Non-Hispanic Asian and Pacific Islander  ****	****	**
**(6) Hispanic origin total**

- U.S. Census Bureau

**Notes:**
Due to many small or empty data cells for some race groups, the age-specific fertility rates by race and Hispanic origin will not be reliable for projections for some states.  Therefore, we prepare only 6 groups and apply them to appropriate groups.

In principle, all the rates for the six basic race groups were prepared for every state.  However,if the numbers for particular race groups are too small to produce reliable rates, the national rates were used. 

These require an extensive review.

## Mortality Input Data

**Deaths by age, sex, race and Hispanic origin **
**1989, 1990, 1991, 1999, 2000, and 2001 **
**Census 2000 by single years of age (0 ~ 100+), sex, race, and Hispanic origin (Bridged race groups)**
**Mortality rates by race and Hispanic origin**
**Same as fertility rates by race, only prepare 6 race / Hispanic groups and apply the mortality rates to appropriate race groups **
**Prepare complete life tables and survival rates**
**Development of mortality changes by state  (1990-2000)**

- U.S. Census Bureau

**Notes:**
To deal with mortality input data, we need to do the tasks shown on the slide.

## Internal Migration Input Data

**IRS region-to-state and state-to-region annual migration flows (1975 – 2003 time series): **
**For projecting total internal migration into the future**
**Census 2000 region-to-state and state-to-region migration flows between 1995 and 2000 by age, sex, race, and Hispanic origin**
**For projecting the composition of internal migration by age, sex, race, and Hispanic demographic detail, controlled to projected IRS migration flows**
**Data issues about 2,550 state-to-state migration flows**
**Many small flows**
**Empty data cells by demographic detail**

- U.S. Census Bureau

## International Migration Input Data

**Estimates of net international migration rates by state 2001-2004**
**Foreign-born population entering the U.S. by age, sex,  race, and Hispanic origin, 1995-2000**
**Projected national net international migration by age, sex, race and Hispanic origin**

- U.S. Census Bureau

## Assumptions

**Fertility: **
**Follow national trends, adjusted by state-specific change in fertility rates (1990-2000)**
**Mortality:**
**Follow national trends, adjusted by state-specific change in mortality rates (1990-2000)**
**Internal migration:**
**Follow the IRS migration trends in region-to-state and state-to-region migration flows.**
**Hold the composition of 1995-2000 census migration flows constant.**
**International migration:**
**Follow current international migration trends in the states and determined by projected net international migration for the U.S.**
**Hold constant the composition of 1995-2000 immigrant population in the state**

- U.S. Census Bureau

**Notes:**
The input data needed also depend on the assumptions we made.

## Fertility Rate Projection 

**Population base **
**Female 14-48+ base year population**
**Female 15-49+ expected survived population**
**Project fertility rates**
**Starting age-specific fertility rates... ***(f(t-1))*
**Projected national total fertility rates...** *(F(t))*
**Ratio of state total fertility rate change to national total fertility change...****	****    ****	****	****	****	****	****	***[f(2000)/f(1990)]/[F(2000 /F(1990)]*
**Projection formula:**
***f(t) = f(t-1) + (F(t) - F(t-1)) *  [(f(2000)/f(1990)) / ******	******	******	******	******	******	******      (F(2000)/F(1990))]***
**	****	****	****	****	**

- U.S. Census Bureau

## Survival Rate Projection

**Project survival rates**
**Starting age-specific survival rates... ***(s(t-1))*
**Projected national survival rates...** *(Sn(t))*
**Adjustment factor – Ratio of state-specific survival rate change to national survival rate change, using one minus probability of dying (1-Qx) by 5-year age...  *****[s(2000)/s(1990)]**** / **	**	**	**	**	**	**	**[****Sn(2000)/Sn(1990)]***
**Projection formula:**
***s(t) = s(t-1) + (Sn(t) – Sn(t-1)) *  [(s(2000)/s(1990)) / ******	******	******	******	******	******	******      (Sn(2000)/Sn(1990))]***
**	****	****	****	**

- U.S. Census Bureau

## Projection of IRS Migration Flows

**Input time series (28 data points): **
**204 region-to-state migration rates (1975-1976 to 2002-2003)**
**204 state-to-region migration rates (1975-1976 to 2001-2003)**
**ARIMA time series projections of first difference in natural log of migration rates for the first 5 years (Using SAS program)**
**Interpolation from 5****th**** year projected migration rates toward mean in the next 20 years**
**Hold the mean constant for remaining projection years**
**	****	****	****	**

- U.S. Census Bureau

**Notes:**
From the St9900in.xls, the original flat file with each column for each variable.  We can use Pivot Table function to tabulate the data in a flash.

The template.xls is to tabulate these Pivote Tables into State-to-State flows

## International Migration Projection

**Project total net international migration by state based on the estimates of net international migration, 2000-2004  **
**Project composition of net international migration **
**Population base**
**Proportion of foreign-born population**
**Control to projected total net international migration **
**Control to projected national international migration for the U.S.**

- U.S. Census Bureau

## Proposed Products

**Detailed age, sex, race, and Hispanic origin for all states, year by year (2005-2030)**
**Detailed age, sex, race, and Hispanic origin with components annually for individual states**
**Summary tables with statistics such as median age, dependency ratio, sex ratio, etc. and graphs such as population pyramids. **

- U.S. Census Bureau

## Slide 25

- U.S. Census Bureau

## Slide 26

- U.S. Census Bureau