Population forecasts are estimates of the future population of a given area. Forecasts are based on an analysis of historic population growth and assumptions about future demographic and economic trends that an analyst believes will occur. Forecasts reflect and incorporate the expertise, judgments and decisions of the analyst with respect to factors such as the integrity of the base data used, the appropriateness of the statistical model employed and the reliability of the assumptions considered. In short, forecasts are an educated best guess of what the future population of an area will be.
The Oregon Administrative Rule 660-024-0030(2) states:
“forecast[s] must take into account documented long-term demographic trends as well as recent events that have a reasonable likelihood of changing historical trends. The population forecast is an estimate which, although based on the best available information and methodology, should not be held to an unreasonably high level of precision.”
Local governments in Oregon have developed and adopted population forecasts for planning purposes since the inception of the statewide planning program. The forecasts are used for many purposes including; determining the size of Urban Growth Boundaries (UGBs), capital improvement planning, and other planning activities. For example, Oregon State planning law (ORS 197.295 – 197.296) requires cities to plan for needed housing to accommodate population growth in urban growth boundaries. ORS 197.712 also requires cities to ensure that sufficient land is available in urban growth boundaries for commercial development and economic growth. Population forecasts are a major determinate in these activities.
2. Why is Lane County undertaking this effort?
All counties in Oregon must coordinate with the cities to develop population forecasts for use by the county and cities in land-use planning activities. ORS 195.036 pertaining to area population forecast coordination states:
“The coordinating body under ORS 195.025(1) shall establish and maintain a population forecast for the entire area within its boundary for use in maintaining and updating comprehensive plans, and shall coordinate the forecast with the local governments within its boundary.”
Lane County is the coordinating body under ORS 195.025(1) regarding regional coordination of planning activities, which states:
“In addition to the responsibilities stated in ORS 197.175, each county, through its governing body, shall be responsible for coordinating all planning activities affecting land uses within the county, including planning activities of the county, cities, special districts and state agencies, to assure an integrated comprehensive plan for the entire area of the county.”
3. How will the population forecasts be developed?
The Portland State University Population Research Center (PRC), under contract with Lane County, will be responsible for the technical and analytical aspects of developing the forecasts. PRC is an interdisciplinary public service, research, and training unit focused on population-related data and research for the State of Oregon. The mission of PRC is to provide population data, information, and research analysis for Oregon and its communities.
The Population Research Center was selected by the Lane County Board of Commissioners to conduct the analytical component of this work because they are widely recognized as objective experts in the field of demography and population analysis.
Under the direction of Lane County Land Management Division, the Population Research Center will develop coordinated twenty-year population forecasts for Lane County and its incorporated communities consistent with the requirements of ORS 195.036. Forecasts will be developed using commonly accepted practices and standards (per OAR 660-024-0030). Developed forecast will then be brought forward as a Post Acknowledgement Plan Amendment to the Lane County Rural Comprehensive Plan (RCP) and, upon adoption, will be referenced in RCP as an Addendum to the Population Working Paper.
As the coordinating body under ORS 195.025, Lane County will seek to adopt forecasts that are:
Responsive to the planning needs of the Lane County and its incorporated cities
Developed using commonly accepted standards and practices in the field of demography
Based upon current, reliable and objective sources of verifiable information such as: birth and death rates, immigration and emigration rates, building permits, land use patterns and census data
Conducted in an open and transparent manner with opportunity for public review and comment
4. How can I participate in this process?
Broad-based, public participation is critical in the development of accurate and legitimate population forecasts. Lane County staff support and encourage citizen involvement efforts that provide for early and active participation by the region’s citizens and interest groups. Throughout the forecast development process and Post Acknowledgment Plan Amendment period there will be multiple opportunities for public involvement and dialogue.
A work program for the project has been developed and approved by the Lane County Board of Commissioners. This work program outlines opportunities for public input and involvement. In addition to this work program a tentative calendar of events is available. As workshops, public hearings and other opportunities for public involvement are formalized the calendar of events will be updated.
In addition to posting this calendar, staff will be sending out invitations for public workshops to known parties of interest and sending official notices of public hearings to parties of record.
Staff report for Board of Commissioners' work session on August 5, 2008
July 24, 2008 PRC Research Proposal for Lane County 2035 Population Forecasts
LMD Population Forecast Work Program
Calendar of Events (dates subject to change)
Project Updates and Events:
On December 2, Lane County hosted a kick-off meeting to familiarize the public about this project and to seek input from citizens, municipalities and other interests. At the meeting staff from the Portland State Population Research Center presented an overview of standard population forecasting techniques.
An agenda for the December 2, Kick-of Meeting can be downloaded, here.
A copy of PSU’s slide show can be downloaded, here .
The video of PSU's presentation can be viewed, here.
Minutes for the December 2, kick-off meeting can be downloaded, here .
Preliminary Population Forecasts Now Available!
February 6, 2009: The Portland State University Population Research Center has released preliminary population forecasts for review by city and county staff and other interested parties. These figures are available for download in Adobe PDF or Microsoft Excel format. Paper copies of the preliminary forecast tables may be requested from the Lane County Land Management Division.
The preliminary forecasts can be downloaded in Excel format, here and in PDF, here .
A coordination meeting was held at 6:00pm on Thursday February 26, for city and county staff and the public to review and discuss the preliminary numbers.
On March 26, 2009, Lane County will host a second coordination meeting. The purpose of this meeting is for city and county staff and the public to review and discuss revised and preliminary forecast number released by the PSU -Population Research Center on March 19.
An agenda for the March 26 coordination meeting can be downloaded, here .
To view the revised preliminary forecast numbers click, here
Population Forecasts Report Released:
May 8, 2009, The Portland State - Population Research Center has released their forecast report for Lane County. In addition to the specific forecasts figures for the county and cities, the report also includes detailed information on:
The trends affecting Lane County populations;
The demographic assumptions used in the forecasts;
The specific methodologies and models employed to formulate the forecasts, and
The data sources used
The report may be downloaded, here .
Population Forecasts Adopted:
On June 17, 2009, the Lane County Board of Commissioners voted unanimously in support of Ordinance No. PA 1255 , thus adopting a coordinated 20-year population forecast for Lane County and each of its urban areas.
A copy of Ordinance PA 1255 may be downloaded, here .