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13 Interpreting the Recommendations The outcome of TFGuide is a menu of recommendations for methods or method packages that the user may consider in the plan or program. It is termed a âmenuâ because several individual or connected methods may be feasible within the user-supplied budget or schedule. Figure 11 shows the menu of recommendations for an example transit corridor study. The menu contains scores that are simple tallies of the requirements, performance metrics, and supplied constraints met by each method package. The first item in the menu of recommendations is the score for current methods and resources if any were supplied. This gives the user a sense of how current methods and resources address the planning study, based on the requirements, performance measures, and constraints specified in Steps 1 through 4. Recommendations for methods or method packages follow, ranked to show the recommendations with the highest scores first. All possible recommendations that meet one or more requirements are provided, so the menu of recommendations can (at times) be lengthy. The user would typically review only the top 10 method recommendations to identify the most promising new methods. The user can expand any method package recommendation to view the scores contributing to the computed tally. The user can also change the budget, schedule, and weight for any TFGuide dimension by using the left-bar features. (Depending on the complexity of the menu, this update can take a few seconds to load after each change.) Users may also want to print their results to share. The first icon in the upper right ( ) allows users to toggle between a condensed menu and a fully expanded menu. A second icon ( ) formats the web page into a printer-friendly layout. The user can reveal chosen parameters within the left bar by clicking any element. The user must navigate back to the appropriate step to make any changes to these elements. The expanded menu in Figure 12 provides the scoring details on the left and the resources breakdown on the right. Both contain crucial background information to illustrate how the ranked scoring was completed. The appendices (reference guide built into TFGuideâs menu) provide many back- ground details that users can explore. The contribution score is calculated by assigning one point for each requirement or met- ric that the method addresses. If there are multiple selections that can be met under a single category for performance metrics or sensitivities, then there is one point assigned for each item and the contribution score shows the total. The industry adoption metric receives one point for a method that is somewhat proven, and two points if the method is proven and validated. Evaluating Results C H A P T E R 4
Figure 11. Example menu of method recommendations.
Figure 12. Example expanded menu of method recommendations.
16 Method Selection for Travel Forecasting: User Guide Budgets and schedules are scored along with other requirements and performance measures. Consistent with how the requirements and performance metrics are scored, budgets and sched- ules contribute to a score but are not used to eliminate recommendations that fall outside these constraints. The scoring for budgets uses a ratio of the budget to cost; methods that cost less than the budget receive higher scores and methods that cost more than the budget receive lower scores. Costs that are more than double the budget will receive a score of zero. A similar approach is used to score the schedule and time frame. The user can adjust the scoring by applying weights to the requirements, performance measures, and constraints. If budget is the most important criterion for identifying a method, then budget can be weighted higher than any other criteria. If vehicle miles traveled is the most important out- come of the method, then it can be weighted higher. The weights are originally input during Steps 1 through 5, but they can be updated on the recommendations page. The bottom of the method package breakdown screen includes a bar that can be used to scroll left or right across multiple methods. This scroll bar will only be available if there are three or more methods included in a recommendation. Users are encouraged to continue refining inputs and weights (as needed) after exploring the methods packages. The work is automatically saved under the existing scenario, which can be referenced later. Managing Existing Scenarios The work completed for a scenario or set of scenarios will be automatically saved by TFGuide. These are then presented on the siteâs Scenario screen (Figure 13) for future reference or adjust- ment. (Note that this beta version allows any user to see all saved scenarios.) A few scenarios have been saved in this beta version as examples. Figure 13. Home page with existing scenarios listed for a user.
Evaluating Results 17 Using the Reference Guide Users can learn about any method, program, requirement, resource, or performance metric in TFGuideâs reference guide. The purpose of this detailed reference guide is twofold: It provides (1) descriptive information for users to learn and (2) the relationships of the methods to each of the core TFGuide elements. For any method, the reference guide (Appendix A) will list any lower-class methods and method relationships; this is crucial to understanding the applicationâs logic in its menu of recommendations. The reference guide provides a brief description of each item, relevant details about each item, and relevant relationships between items in the decision-support system. An example descrip- tion of the fixed-factor mode choice method is provided in Figure 14. References to assist users in understanding are provided for each method and are combined in the References section at the end of Appendix A. The reference guide can be accessed three ways: 1. Appendices A through E of this user guide. 2. Interactively in TFGuide. 3. Exported to a Microsoft® Word⢠document from TFGuide. Figure 14. Example description for a method in the reference guide.
