Text Size:   A+ A- A   •   Text Only
Site Image

Step 5: Develop and Evaluate Alternative Scenarios


Step 5 is the essence of scenario planning: engaging the public, stakeholders and decision-makers in a broad public discussion about different options for the area’s future. Involving the public is critical to evaluating the pluses and minuses of different choices, and identifying realistic options. The community is invited to consider how changing economics, demographics and social conditions affect the community’s prospects and options for the future. Finally, public involvement in evaluating a range of choices sets the stage for developing and selecting a preferred scenario in Step 6 that best achieves community goals and objectives.


Step 5 involves developing and evaluating alternative scenarios evaluate the long-term results of a variety of different policy decisions and assumptions, as well as testing land use and transportation strategies known to reduce GHG emissions from light vehicles. These alternative scenarios are evaluated and compared against each other, and against the reference case developed in Step 4, in a public process. The public is engaged in testing alternative policy options such as adjusting land use allocations and codes, different transportation investments, expanded bicycle and pedestrian programs, and other possible changes, to evaluate their effectiveness and feasibility based on issues most important to the community.

Metropolitan GreenSTEP can be used to perform a high-level strategic assessment of potential alternative scenarios before embarking on the more detailed analysis utilizing a sketch planning tool and the public process. In this step, alternatives go from a theoretical discussion of themes that address the needs and interests of the community to the actual testing of specific policy choices through evaluation of alternative scenarios.

Public Engagement

Step 4 recommended methods for presenting the base year conditions and reference case evaluation to the public to get input about what should come next. The results of that conversation set the stage for this step: developing alternative scenarios. At this point, a preliminary run of Metropolitan GreenSTEP is recommended to strategically assess a wide range of scenario theme options, which can inform the selection of alternative scenarios, before embarking on a more detailed and time consuming process.

During the creation of alternative scenarios, the public and stakeholders should be highly engaged in the process and take a prominent role in the scenario development process. Elected officials should focus on bringing stakeholders to the table. Through their own work sessions, elected officials can help to develop scenario concepts and also review concepts generated through the public workshops. Their involvement as participants will legitimize the process in the eyes of their constituents.

Creation of several different alternative scenarios is a key point in the process, and public involvement is critical. People care about their neighborhoods and their community’s future, and typically have strong feelings about what they would like that future to be. Therefore, it is important they have a role in designing the choices to be considered. Building public understanding of existing plans and their likely outcomes ensures that everyone participating has a common frame of reference. This expanded understanding helps those involved work together to formulate and evaluate options.

Creating and testing a variety of regional scenarios in this step provides the public with a unique opportunity to participate in long-range planning for their community. The interactive workshop is an effective and engaging tool in developing alternative scenarios. Today’s technology allows workshops to include video, interactive polling, and use of GIS data, along with traditional presentations and small group table exercises.

Since not everyone will be able to attend these workshops or meetings, there should be additional efforts to inform and consult with members of the public who did not attend. Traditional methods such as fact sheets, newspaper articles, and providing guest speakers at community meetings (e.g. Rotary, PTA, neighborhood association) are useful. Use of popular social networks should also be considered. (See the Technical Appendix for more information about using these tools.)

Using the Step 4 report card that summarizes Base Case and Reference scenario evaluations, the public and stakeholders are provided with valuable insight on what the future may hold. The ability for participants to help reshape, or even confirm some of the expected outcomes, can provide additional motivation to stay involved.

The important public engagement goal of this step is to solicit ideas from the community that would be useful in building scenarios of the future. Their input is informed by the evaluation of the base conditions and reference case presented in the report card from Step 4. To begin the conversation about what the region could do to improve the future, the public should be invited to share their visions for the region and provide input on policies, actions and programs that should be tested in the scenarios. Step 2 identified the values and guiding principles for the metropolitan area that should also be used to inform the selection of themes for scenarios.

Two examples of public engagement at this stage in the scenario planning effort are summarized below. A full-fledged public engagement effort can also draw from options described in more detail in the Technical Appendix.
Workshops and Public Meetings
The purpose of public engagement at this step is to collect ideas to refine the initial set of scenarios or develop new scenarios. The challenge is to design engagement activities that nurture awareness and ownership of the process and yet still fit within budgeted funds and staff resources. Expenses and staff time can be managed by limiting the number of events, and using low-cost, effective outreach technologies such as interactive polling. (For more about cost-effective outreach strategies, see the Step-by-Step Public Involvement section of the Technical Appendix.

Most of Oregon’s metropolitan areas should be able to gather quality input with one or two centrally located workshops and/or meetings. Occasionally, additional meetings may be necessary for specific subareas where significant changes may be occurring or to involve specific interest groups such as minority communities, business people, students, and other stakeholders. However, it is important to avoid hosting too many events in order to moderate costs as well as to ensure as large as possible turn-outs for each single event. Too few interested participants at a meeting or workshop make it difficult to achieve the sort of critical mass often necessary for creative thinking.

The Step 1 public engagement plan should now be revisited to ensure that planned efforts and activities will reach key audiences and provide the information stakeholders need in order to understand the scenarios and provide meaningful input. Consider potential issues, such as:
  1. What new information is available about the community’s likely future that would trigger public interest or concern? How well do existing plans help the community achieve the guiding principles identified in Step 2? What was learned from the development and evaluation of the base year conditions and reference case in Step 4? Examining the reference case in light of the guiding principles from Step 2 may provide valuable insight into what types of issues the public will want to work on.
  2. Has the project schedule shifted? Public engagement is most effective during the school year, minus the winter holiday season. If schedules have shifted, it may be worth reconsidering the scheduling of public events.
  3. Are people ready to engage in a workshop? Gauge responses from previous meetings, correspondence and website visits to get an idea of what sort of turnout is likely. Look at who has participated thus far to see if your plan may need to change in order to reach across the entire metropolitan area.
Map-based or computer-based scenario workshops can produce the data needed to inform the construction of the alternative scenarios. It is important for these workshops to be interesting and allow the public to grapple with trade-offs, sharing what they learn with other community members. Linked below is information about three workshop styles that could be employed as part of the public engagement process to develop alternative scenarios. More information is in the Technical Appendix.

Develop Alternative Scenarios

The ideas and concepts that emerged from public review and evaluation of the Base Case and the Reference Scenario should now be compiled and summarized to identify themes for use in designing alternative scenarios. The number of alternatives to be developed depends on available time, resources and the complexity of the selected scenario themes.

Typically, scenarios go through a series of iterations as planners work to produce the desired outcomes. The recommended number of alternative scenarios to be developed is four. The nuances between five or more can be difficult to understand, and using only three seems to imply a preference for the middle scenario. Typically, the reference case is included as one of these four alternatives.
Alternative Scenario Themes
Themes can range from recent trends to modifications of the reference case (like improving jobs-to-housing balance) to those based on specific drivers (like housing or economic development forecasts). The selected scenario themes should be as distinct as possible, so that the choices defining each scenario are clear, and the differences between them are easily distinguished. When selecting themes for scenarios, alternative scenarios that push the limits of a particular policy option or theme should be considered.

The purpose of alternative scenarios is to illustrate differences between possible choices. This is especially important if the metropolitan area is not rapidly growing. It may be that 75% or more of the jobs and housing in the planning year were already on the ground at the time of the base case. Subtle changes in housing styles or lot sizes for example, may not significantly “move the needle” since only a minority of the population would be able to take advantage of new housing options. Scenarios, at this point, are not specific proposals for how plans might be changed, they illustrate the range of possible outcomes and inform selection of a preferred alternative.

Below are some scenario themes to use for guidance. This is not an exhaustive list, nor do these themes need to remain segregated. For example, testing increases in infill housing could be in a scenario based on recent trends, but also in one aimed at examining land use practices shown to reduce GHG emissions.

Evaluate the Alternative Scenarios

Evaluate the performance of alternative scenarios is evaluated using the criteria from Step 2, sketch planning tools, and Metropolitan GreenSTEP. This process is identical to that described in Step 4 regarding the reference case scenario. A portion of the evaluation criteria identified in Step 2 will come from Metropolitan GreenSTEP, while others will be direct results of using a sketch planning tool.

As discussed in Step 3, the recommended approach is to start with a high-level strategic assessment using Metropolitan GreenSTEP, then link the more detailed land use and urban design information produced by the sketch planning tool back into Metropolitan GreenSTEP for evaluation. Evaluate each alternative scenario against the same evaluation criteria used with the reference, for easy comparison. Be sure to do a “reality check” against known local trends and projections.

The best approach is to highlight differences between the scenarios, not the absolute numbers. For example, announcing that a scenario models 16.7 VMT per day, may be too abstract for most people to understand. It is easier to visualize the meaning of those results when the evaluation is compared with the VMT from the Base Case, Reference case, and other alternative scenarios. Adding measures such as the average per capita fuel costs will go even further to making a measure such as VMT more meaningful. When preparing the evaluation of the scenarios to be shared with the public and policy makers in Step 6 use language and graphics that communicate the issues in a manner to which people can relate.


Themes for the development of alternative scenarios were initially selected through a high-level strategic assessment of many possible alternatives, using Metropolitan GreenSTEP, and later through a more detailed sketch planning process with broader public engagement. Through the early GreenSTEP phase decision-makers, stakeholders and the public can explore and discuss the land use and transportation choices the community faces in addressing important issues over the next 20 years, or more, and test those choices in alternative scenarios.

Through the more detailed sketch planning phase of the process, the general public enters into the conversation with decision makers and stakeholders about the future of their community. Based on the selected themes, several alternative scenarios for the metropolitan area are designed and evaluate. The results of those evaluations are reported back to the public and stakeholders in Step 6 to inform the selection of a preferred scenario, which will include a concept map and a set of major programs, policies or general actions, and spatially distributed housing and employment forecasts.