Scenario Description - Revision history

Ethan.Sullivan at 10:39, 5 August 2025

2025-08-05T10:39:12Z

← Older revision		Revision as of 10:39, 5 August 2025
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	In addition to the base case, some versions of IFs will include a number of other previously-run scenarios, perhaps the set of scenarios for the National Intelligence Council’s (NIC) 2020 Project or those for the five Shared Socioeconomic Pathways. In the '''Scenarios''' drop down in Flex Displays, a list of previously-run scenarios is shown before any new scenarios are run. Because those have already been run, based on a set of interventions constituting their foundations, their results can already be displayed.		In addition to the base case, some versions of IFs will include a number of other previously-run scenarios, perhaps the set of scenarios for the National Intelligence Council’s (NIC) 2020 Project or those for the five Shared Socioeconomic Pathways. In the '''Scenarios''' drop down in Flex Displays, a list of previously-run scenarios is shown before any new scenarios are run. Because those have already been run, based on a set of interventions constituting their foundations, their results can already be displayed.

	=<span style="font-size:xx-large;">Parameter Types</span>=		= <span style="font-size:xx-large;">Parameter Types</span> =
	Parameters are numbers that determine relationships among variables in the equations of IFs. Parameters are often set to a single value across time and they therefore do not always "vary" as do "real" variables. Many parameters are "policy handles," the value of which is set in order to determine the behavior of the model. In IFs parameters are written in lower case form such as endemm and variables are written in upper case such as ENDEM. There are several types of parameters that include:		Parameters are numbers that determine relationships among variables in the equations of IFs. Parameters are often set to a single value across time and they therefore do not always "vary" as do "real" variables. Many parameters are "policy handles," the value of which is set in order to determine the behavior of the model. In IFs parameters are written in lower case form such as endemm and variables are written in upper case such as ENDEM. There are several types of parameters that include:

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	The focus here is on exogenous parameters only - on those elements of the model that you can change. Many computed variables are used in the computation of other variables in the same way that parameters are, as multipliers, additive factors, coefficients, and so on. You can display those, but unlike true parameters, you cannot change them.		The focus here is on exogenous parameters only - on those elements of the model that you can change. Many computed variables are used in the computation of other variables in the same way that parameters are, as multipliers, additive factors, coefficients, and so on. You can display those, but unlike true parameters, you cannot change them.
	=<span style="font-size:xx-large;">Understanding Model Computations</span>=
			= <span style="font-size:xx-large;">Understanding Model Computations</span> =
	It is critical that there be as much transparency as possible with respect to computations that underlie the variables chosen for display. In a large, integrated model, achieving such transparency is not simple. Look at the pages under the extensive Help section called [[Understand the Model\|"’Understand IFs"]] for extensive documentation via flow charts, equations, and computer code.		It is critical that there be as much transparency as possible with respect to computations that underlie the variables chosen for display. In a large, integrated model, achieving such transparency is not simple. Look at the pages under the extensive Help section called [[Understand the Model\|"’Understand IFs"]] for extensive documentation via flow charts, equations, and computer code.

	While working with display of variables, however, there are several ways in which to drill down for explanations of what lies behind their computations. After a variable or parameter is added to the Quick Scenario with Tree, learn more about how a parameter or variable is generated by clicking on it and exploring the options.		While working with display of variables, however, there are several ways in which to drill down for explanations of what lies behind their computations. After a variable or parameter is added to the Quick Scenario with Tree, learn more about how a parameter or variable is generated by clicking on it and exploring the options.

Ethan.Sullivan: /* Parameter Types */

2025-08-05T10:38:43Z

Parameter Types

Show changes

Ethan.Sullivan at 14:33, 4 August 2025

2025-08-04T14:33:11Z

← Older revision		Revision as of 14:33, 4 August 2025
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	'''Switches.''' These parameters turn something on or off. They generally take on values of 1 (on) or 0 (off), but can have additional settings. For instance, some switches not only turn on some process, but set a key value within it (like the level of energy exports). Switches are most often on or off for the entire run, but it sometimes makes sense to "throw a switch" in the middle of a run. Switches allow you to fundamentally alter the structure of a model. Switches include: ACTREAON, AGON, ALLY, ENON, ENTL, ENPRIX, and SQUEEZ.		'''Switches.''' These parameters turn something on or off. They generally take on values of 1 (on) or 0 (off), but can have additional settings. For instance, some switches not only turn on some process, but set a key value within it (like the level of energy exports). Switches are most often on or off for the entire run, but it sometimes makes sense to "throw a switch" in the middle of a run. Switches allow you to fundamentally alter the structure of a model. Switches include: ACTREAON, AGON, ALLY, ENON, ENTL, ENPRIX, and SQUEEZ.

			'''Relationship: Finally, if you choose a parameter in the Relationship Parameters category, you will be able to change the relationship between two different parameters. You may want to change the mathematical relationships in the "black-box".'''

	The focus here is on exogenous parameters only - on those elements of the model that you can change. Many computed variables are used in the computation of other variables in the same way that parameters are, as multipliers, additive factors, coefficients, and so on. You can display those, but unlike true parameters, you cannot change them.		The focus here is on exogenous parameters only - on those elements of the model that you can change. Many computed variables are used in the computation of other variables in the same way that parameters are, as multipliers, additive factors, coefficients, and so on. You can display those, but unlike true parameters, you cannot change them.

Ethan.Sullivan at 15:45, 1 August 2025

2025-08-01T15:45:43Z

@@ Line 1: / Line 1: @@
 A scenario is a story or story outline. Thinking about the future normally involves creating alternative scenarios, or stories, about the possible evolution of drivers. Some such scenarios are exploratory and consider the possible unfolding of different futures around key uncertainties, such as the rate of some aspect of technological advance or the fragility of some element in the global environment. Other scenarios are normative and develop stories about preferred futures, such as a global transformation to sustainability.
@@ Line 5: / Line 6: @@
 Scenarios or interventions with respect to what? When IFs or other computer simulations are "run", without making any changes to parameters or initial conditions specified as the default values, they generate a forecast that is typically called the base case (sometimes reference run). The IFs base case, always available when a model session is initiated, is itself a scenario. Sometimes the base case is incorrectly referred to as a trend extrapolation or a "business as usual" scenario. More accurately, however, the base case of IFs is a computation that involves the full dynamics of the model and therefore has very nonlinear behavior, often quite different from trends. It is a good starting point for scenario analysis for two reasons. First, it is built from initial conditions of all variables and on that has been given reasonable values from data or other analysis. These initial conditions and parameters make up the package of interventions that constitute the base case scenario. Second, the base case is periodically analyzed relative to the forecasts of many other projects across the range of issue areas covered by IFs and is to a degree "tuned" to reproduce the behavior of respected forecasters.
-The&nbsp;[[Quick_Scenario_Analysis_with_Tree|Quick Scenario Tree]]&nbsp;allows users to create and save two different kinds of files: Scenario-Load-Files (.sce) and Run-Result-Files (.run). The Scenario-Load-Files files represent changes that were made to the scenario tree but that were not yet entirely run through IFs software. The Run-Result-Files represent files that were originally changes to the scenario tree that were eventually entirely run through IFs software. The running a Scenario-Load-Files file will make those changes permanent and therefore a Run-Result-File.
+Change initial conditions and parameters using the  [[Quick Scenario Analysis with Tree|Quick Scenario Tree]]  to create scenarios beyond the base case. Adjust parameters to make specific intended interventions, for example use the Government Spending by Destination and Sector multiplier parameter gdsm to increase government spending in education. A detailed guide of the different parameters and their potential uses can be found in the [[Guide to Scenario Analysis in International Futures (IFs)|Guide to Scenario Analysis]].
-In addition to the base case, most versions of IFs will include a number of other previously-run scenarios (see&nbsp;[[How_Do_I...?_Lessons_0-4#Lesson_0:_IFs_Vocabulary|Lesson 0]]&nbsp;for additional important terminology), perhaps the set of scenarios for the National Intelligence Council’s (NIC) 2020 Project or those for the Global Environmental Outlook (GEO) of the United Nations Environmental Program. If you look, for instance, at the Packaged Display form, you will see a list of previously-run scenarios in the box at the bottom left of the screen. Because those have already been run, based on a set of interventions constituting their foundations, the user can immediately display their results.
+Use the  [[Quick Scenario Analysis with Tree|Quick Scenario Tree]]  to create and save two different kinds of files: Scenario-Load-Files (.sce) and Run-Result-Files (.run). The Scenario-Load-Files files represent changes that were made to the scenario tree but that were not yet entirely run through IFs software. The Run-Result-Files represent files that were originally changes to the scenario tree that were eventually entirely run through IFs software. The running of a Scenario-Load-Files file will make those changes permanent and therefore produce a Run-Result-File.

Ethan.Sullivan at 15:36, 1 August 2025

2025-08-01T15:36:55Z

← Older revision		Revision as of 15:36, 1 August 2025
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	Scenarios or interventions with respect to what? When IFs or other computer simulations are "run", without making any changes to parameters or initial conditions specified as the default values, they generate a forecast that is typically called the base case (sometimes reference run). The IFs base case, always available when a model session is initiated, is itself a scenario. Sometimes the base case is incorrectly referred to as a trend extrapolation or a "business as usual" scenario. More accurately, however, the base case of IFs is a computation that involves the full dynamics of the model and therefore has very nonlinear behavior, often quite different from trends. It is a good starting point for scenario analysis for two reasons. First, it is built from initial conditions of all variables and on that has been given reasonable values from data or other analysis. These initial conditions and parameters make up the package of interventions that constitute the base case scenario. Second, the base case is periodically analyzed relative to the forecasts of many other projects across the range of issue areas covered by IFs and is to a degree "tuned" to reproduce the behavior of respected forecasters.		Scenarios or interventions with respect to what? When IFs or other computer simulations are "run", without making any changes to parameters or initial conditions specified as the default values, they generate a forecast that is typically called the base case (sometimes reference run). The IFs base case, always available when a model session is initiated, is itself a scenario. Sometimes the base case is incorrectly referred to as a trend extrapolation or a "business as usual" scenario. More accurately, however, the base case of IFs is a computation that involves the full dynamics of the model and therefore has very nonlinear behavior, often quite different from trends. It is a good starting point for scenario analysis for two reasons. First, it is built from initial conditions of all variables and on that has been given reasonable values from data or other analysis. These initial conditions and parameters make up the package of interventions that constitute the base case scenario. Second, the base case is periodically analyzed relative to the forecasts of many other projects across the range of issue areas covered by IFs and is to a degree "tuned" to reproduce the behavior of respected forecasters.

	Change initial conditions and parameters using the  [[Quick_Scenario_Analysis_with_Tree\|Quick Scenario Tree]]  to create scenarios beyond the base case. Adjust parameters to make specific intended interventions, for example use the Government Spending by Destination and Sector multiplier parameter gdsm to increase government spending in education. A detailed guide of the different parameters and their potential uses can be found in the [[Guide to Scenario Analysis in International Futures (IFs)\|Guide to Scenario Analysis]].

	The [[Quick_Scenario_Analysis_with_Tree\|Quick Scenario Tree]] allows users to create and save two different kinds of files: Scenario-Load-Files (.sce) and Run-Result-Files (.run). The Scenario-Load-Files files represent changes that were made to the scenario tree but that were not yet entirely run through IFs software. The Run-Result-Files represent files that were originally changes to the scenario tree that were eventually entirely run through IFs software. The running a Scenario-Load-Files file will make those changes permanent and therefore a Run-Result-File.		The [[Quick_Scenario_Analysis_with_Tree\|Quick Scenario Tree]] allows users to create and save two different kinds of files: Scenario-Load-Files (.sce) and Run-Result-Files (.run). The Scenario-Load-Files files represent changes that were made to the scenario tree but that were not yet entirely run through IFs software. The Run-Result-Files represent files that were originally changes to the scenario tree that were eventually entirely run through IFs software. The running a Scenario-Load-Files file will make those changes permanent and therefore a Run-Result-File.

	In addition to the base case, most versions of IFs will include a number of other previously-run scenarios (see [[How_Do_I...?_Lessons_0-4#Lesson_0:_IFs_Vocabulary\|Lesson 0]] for additional important terminology), perhaps the set of scenarios for the National Intelligence Council’s (NIC) 2020 Project or those for the Global Environmental Outlook (GEO) of the United Nations Environmental Program. If you look, for instance, at the Packaged Display form, you will see a list of previously-run scenarios in the box at the bottom left of the screen. Because those have already been run, based on a set of interventions constituting their foundations, the user can immediately display their results.		In addition to the base case, most versions of IFs will include a number of other previously-run scenarios (see [[How_Do_I...?_Lessons_0-4#Lesson_0:_IFs_Vocabulary\|Lesson 0]] for additional important terminology), perhaps the set of scenarios for the National Intelligence Council’s (NIC) 2020 Project or those for the Global Environmental Outlook (GEO) of the United Nations Environmental Program. If you look, for instance, at the Packaged Display form, you will see a list of previously-run scenarios in the box at the bottom left of the screen. Because those have already been run, based on a set of interventions constituting their foundations, the user can immediately display their results.

Ethan.Sullivan at 15:26, 1 August 2025

2025-08-01T15:26:41Z

← Older revision		Revision as of 15:26, 1 August 2025
Line 5:		Line 5:
	Scenarios or interventions with respect to what? When IFs or other computer simulations are "run", without making any changes to parameters or initial conditions specified as the default values, they generate a forecast that is typically called the base case (sometimes reference run). The IFs base case, always available when a model session is initiated, is itself a scenario. Sometimes the base case is incorrectly referred to as a trend extrapolation or a "business as usual" scenario. More accurately, however, the base case of IFs is a computation that involves the full dynamics of the model and therefore has very nonlinear behavior, often quite different from trends. It is a good starting point for scenario analysis for two reasons. First, it is built from initial conditions of all variables and on that has been given reasonable values from data or other analysis. These initial conditions and parameters make up the package of interventions that constitute the base case scenario. Second, the base case is periodically analyzed relative to the forecasts of many other projects across the range of issue areas covered by IFs and is to a degree "tuned" to reproduce the behavior of respected forecasters.		Scenarios or interventions with respect to what? When IFs or other computer simulations are "run", without making any changes to parameters or initial conditions specified as the default values, they generate a forecast that is typically called the base case (sometimes reference run). The IFs base case, always available when a model session is initiated, is itself a scenario. Sometimes the base case is incorrectly referred to as a trend extrapolation or a "business as usual" scenario. More accurately, however, the base case of IFs is a computation that involves the full dynamics of the model and therefore has very nonlinear behavior, often quite different from trends. It is a good starting point for scenario analysis for two reasons. First, it is built from initial conditions of all variables and on that has been given reasonable values from data or other analysis. These initial conditions and parameters make up the package of interventions that constitute the base case scenario. Second, the base case is periodically analyzed relative to the forecasts of many other projects across the range of issue areas covered by IFs and is to a degree "tuned" to reproduce the behavior of respected forecasters.

	~~Use~~ the  [[Quick_Scenario_Analysis_with_Tree\|Quick Scenario Tree]]  to create and ~~save two~~ different ~~kinds of files:~~ Scenario~~-Load-Files~~ (~~.sce~~) and Run-Result-Files (.run). The Scenario-Load-Files files represent changes that were made to the scenario tree but that were not yet entirely run through IFs software. The Run-Result-Files represent files that were originally changes to ~~the scenario tree that were eventually entirely run through IFs software. The running of a~~ Scenario~~-Load-Files file will make those changes permanent and therefore produce a Run-Result-File~~.		Change initial conditions and parameters using the  [[Quick_Scenario_Analysis_with_Tree\|Quick Scenario Tree]]  to create scenarios beyond the base case. Adjust parameters to make specific intended interventions, for example use the Government Spending by Destination and Sector multiplier parameter gdsm to increase government spending in education. A detailed guide of the different parameters and their potential uses can be found in the [[Guide to Scenario Analysis in International Futures (IFs)\|Guide to Scenario Analysis]].

	In addition to the base case, ~~some~~ versions of IFs will include a number of other previously-run scenarios, perhaps the set of scenarios for the National Intelligence Council’s (NIC) 2020 Project or those for the ~~five Shared Socioeconomic Pathways~~. In the ~~'''Scenarios''' drop down in Flex Displays~~, a list of previously-run scenarios ~~is shown before any new scenarios are run~~. Because those have already been run, based on a set of interventions constituting their foundations, their results ~~can already be displayed~~.		The [[Quick_Scenario_Analysis_with_Tree\|Quick Scenario Tree]] allows users to create and save two different kinds of files: Scenario-Load-Files (.sce) and Run-Result-Files (.run). The Scenario-Load-Files files represent changes that were made to the scenario tree but that were not yet entirely run through IFs software. The Run-Result-Files represent files that were originally changes to the scenario tree that were eventually entirely run through IFs software. The running a Scenario-Load-Files file will make those changes permanent and therefore a Run-Result-File.

			In addition to the base case, most versions of IFs will include a number of other previously-run scenarios (see [[How_Do_I...?_Lessons_0-4#Lesson_0:_IFs_Vocabulary\|Lesson 0]] for additional important terminology), perhaps the set of scenarios for the National Intelligence Council’s (NIC) 2020 Project or those for the Global Environmental Outlook (GEO) of the United Nations Environmental Program. If you look, for instance, at the Packaged Display form, you will see a list of previously-run scenarios in the box at the bottom left of the screen. Because those have already been run, based on a set of interventions constituting their foundations, the user can immediately display their results.

Ethan.Sullivan: Updated some example, replaced second person writing

2025-08-01T14:51:02Z

Updated some example, replaced second person writing

← Older revision		Revision as of 14:51, 1 August 2025
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	Scenarios or interventions with respect to what? When IFs or other computer simulations are "run", without making any changes to parameters or initial conditions specified as the default values, they generate a forecast that is typically called the base case (sometimes reference run). The IFs base case, always available when a model session is initiated, is itself a scenario. Sometimes the base case is incorrectly referred to as a trend extrapolation or a "business as usual" scenario. More accurately, however, the base case of IFs is a computation that involves the full dynamics of the model and therefore has very nonlinear behavior, often quite different from trends. It is a good starting point for scenario analysis for two reasons. First, it is built from initial conditions of all variables and on that has been given reasonable values from data or other analysis. These initial conditions and parameters make up the package of interventions that constitute the base case scenario. Second, the base case is periodically analyzed relative to the forecasts of many other projects across the range of issue areas covered by IFs and is to a degree "tuned" to reproduce the behavior of respected forecasters.		Scenarios or interventions with respect to what? When IFs or other computer simulations are "run", without making any changes to parameters or initial conditions specified as the default values, they generate a forecast that is typically called the base case (sometimes reference run). The IFs base case, always available when a model session is initiated, is itself a scenario. Sometimes the base case is incorrectly referred to as a trend extrapolation or a "business as usual" scenario. More accurately, however, the base case of IFs is a computation that involves the full dynamics of the model and therefore has very nonlinear behavior, often quite different from trends. It is a good starting point for scenario analysis for two reasons. First, it is built from initial conditions of all variables and on that has been given reasonable values from data or other analysis. These initial conditions and parameters make up the package of interventions that constitute the base case scenario. Second, the base case is periodically analyzed relative to the forecasts of many other projects across the range of issue areas covered by IFs and is to a degree "tuned" to reproduce the behavior of respected forecasters.

	~~The~~ [[Quick_Scenario_Analysis_with_Tree\|Quick Scenario Tree]] ~~allows users~~ to create and save two different kinds of files: Scenario-Load-Files (.sce) and Run-Result-Files (.run). The Scenario-Load-Files files represent changes that were made to the scenario tree but that were not yet entirely run through IFs software. The Run-Result-Files represent files that were originally changes to the scenario tree that were eventually entirely run through IFs software. The running a Scenario-Load-Files file will make those changes permanent and therefore a Run-Result-File.		Use the  [[Quick_Scenario_Analysis_with_Tree\|Quick Scenario Tree]]  to create and save two different kinds of files: Scenario-Load-Files (.sce) and Run-Result-Files (.run). The Scenario-Load-Files files represent changes that were made to the scenario tree but that were not yet entirely run through IFs software. The Run-Result-Files represent files that were originally changes to the scenario tree that were eventually entirely run through IFs software. The running of a Scenario-Load-Files file will make those changes permanent and therefore produce a Run-Result-File.

	In addition to the base case, ~~most~~ versions of IFs will include a number of other previously-run scenarios ~~(see [[How_Do_I...?_Lessons_0-4#Lesson_0:_IFs_Vocabulary\|Lesson 0]] for additional important terminology)~~, perhaps the set of scenarios for the National Intelligence Council’s (NIC) 2020 Project or those for the ~~Global Environmental Outlook (GEO) of the United Nations Environmental Program~~. ~~If you look, for instance, at~~ the ~~Packaged Display form~~, ~~you will see~~ a list of previously-run scenarios ~~in the box at the bottom left of the screen~~. Because those have already been run, based on a set of interventions constituting their foundations, ~~the user can immediately display~~ their results.		In addition to the base case, some versions of IFs will include a number of other previously-run scenarios, perhaps the set of scenarios for the National Intelligence Council’s (NIC) 2020 Project or those for the five Shared Socioeconomic Pathways. In the '''Scenarios''' drop down in Flex Displays, a list of previously-run scenarios is shown before any new scenarios are run. Because those have already been run, based on a set of interventions constituting their foundations, their results can already be displayed.

CamrynDreyer at 15:07, 25 July 2017

2017-07-25T15:07:43Z

← Older revision		Revision as of 15:07, 25 July 2017
Line 5:		Line 5:
	Scenarios or interventions with respect to what? When IFs or other computer simulations are "run", without making any changes to parameters or initial conditions specified as the default values, they generate a forecast that is typically called the base case (sometimes reference run). The IFs base case, always available when a model session is initiated, is itself a scenario. Sometimes the base case is incorrectly referred to as a trend extrapolation or a "business as usual" scenario. More accurately, however, the base case of IFs is a computation that involves the full dynamics of the model and therefore has very nonlinear behavior, often quite different from trends. It is a good starting point for scenario analysis for two reasons. First, it is built from initial conditions of all variables and on that has been given reasonable values from data or other analysis. These initial conditions and parameters make up the package of interventions that constitute the base case scenario. Second, the base case is periodically analyzed relative to the forecasts of many other projects across the range of issue areas covered by IFs and is to a degree "tuned" to reproduce the behavior of respected forecasters.		Scenarios or interventions with respect to what? When IFs or other computer simulations are "run", without making any changes to parameters or initial conditions specified as the default values, they generate a forecast that is typically called the base case (sometimes reference run). The IFs base case, always available when a model session is initiated, is itself a scenario. Sometimes the base case is incorrectly referred to as a trend extrapolation or a "business as usual" scenario. More accurately, however, the base case of IFs is a computation that involves the full dynamics of the model and therefore has very nonlinear behavior, often quite different from trends. It is a good starting point for scenario analysis for two reasons. First, it is built from initial conditions of all variables and on that has been given reasonable values from data or other analysis. These initial conditions and parameters make up the package of interventions that constitute the base case scenario. Second, the base case is periodically analyzed relative to the forecasts of many other projects across the range of issue areas covered by IFs and is to a degree "tuned" to reproduce the behavior of respected forecasters.

	The [~~http://www.du.edu/ifs/help/use/scenario/quick/quicktree.html~~ Quick Scenario Tree] allows users to create and save two different kinds of files: Scenario-Load-Files (.sce) and Run-Result-Files (.run). The Scenario-Load-Files files represent changes that were made to the scenario tree but that were not yet entirely run through IFs software. The Run-Result-Files represent files that were originally changes to the scenario tree that were eventually entirely run through IFs software. The running a Scenario-Load-Files file will make those changes permanent and therefore a Run-Result-File.		The [[Quick_Scenario_Analysis_with_Tree\|Quick Scenario Tree]] allows users to create and save two different kinds of files: Scenario-Load-Files (.sce) and Run-Result-Files (.run). The Scenario-Load-Files files represent changes that were made to the scenario tree but that were not yet entirely run through IFs software. The Run-Result-Files represent files that were originally changes to the scenario tree that were eventually entirely run through IFs software. The running a Scenario-Load-Files file will make those changes permanent and therefore a Run-Result-File.

	In addition to the base case, most versions of IFs will include a number of other previously-run scenarios (see [~~http://www~~.du.~~edu/ifs/help/use/howdoi/lesson0~~.~~html~~ Lesson 0] for additional important terminology), perhaps the set of scenarios for the National Intelligence Council’s (NIC) 2020 Project or those for the Global Environmental Outlook (GEO) of the United Nations Environmental Program. If you look, for instance, at the Packaged Display form, you will see a list of previously-run scenarios in the box at the bottom left of the screen. Because those have already been run, based on a set of interventions constituting their foundations, the user can immediately display their results.		In addition to the base case, most versions of IFs will include a number of other previously-run scenarios (see [[How_Do_I...?_Lessons_0-4#Lesson_0:_IFs_Vocabulary\|Lesson 0]] for additional important terminology), perhaps the set of scenarios for the National Intelligence Council’s (NIC) 2020 Project or those for the Global Environmental Outlook (GEO) of the United Nations Environmental Program. If you look, for instance, at the Packaged Display form, you will see a list of previously-run scenarios in the box at the bottom left of the screen. Because those have already been run, based on a set of interventions constituting their foundations, the user can immediately display their results.

EmoryFerguson: Created page with "A scenario is a story or story outline. Thinking about the future normally involves creating alternative scenarios, or stories, about the possible evolution of drivers. Some s..."

2017-07-21T18:30:14Z

Created page with "A scenario is a story or story outline. Thinking about the future normally involves creating alternative scenarios, or stories, about the possible evolution of drivers. Some s..."

New page

A scenario is a story or story outline. Thinking about the future normally involves creating alternative scenarios, or stories, about the possible evolution of drivers. Some such scenarios are exploratory and consider the possible unfolding of different futures around key uncertainties, such as the rate of some aspect of technological advance or the fragility of some element in the global environment. Other scenarios are normative and develop stories about preferred futures, such as a global transformation to sustainability.

Scenarios in a computer model typically are built from multiple interventions that collectively help build a coherent story about the future. Often, but somewhat imprecisely, the word scenario is used more loosely to refer to any intervention (such as the change of a fertility rate for a country or an alternative assumption about oil resources).

Scenarios or interventions with respect to what? When IFs or other computer simulations are "run", without making any changes to parameters or initial conditions specified as the default values, they generate a forecast that is typically called the base case (sometimes reference run). The IFs base case, always available when a model session is initiated, is itself a scenario. Sometimes the base case is incorrectly referred to as a trend extrapolation or a "business as usual" scenario. More accurately, however, the base case of IFs is a computation that involves the full dynamics of the model and therefore has very nonlinear behavior, often quite different from trends. It is a good starting point for scenario analysis for two reasons. First, it is built from initial conditions of all variables and on that has been given reasonable values from data or other analysis. These initial conditions and parameters make up the package of interventions that constitute the base case scenario. Second, the base case is periodically analyzed relative to the forecasts of many other projects across the range of issue areas covered by IFs and is to a degree "tuned" to reproduce the behavior of respected forecasters.

The [http://www.du.edu/ifs/help/use/scenario/quick/quicktree.html Quick Scenario Tree] allows users to create and save two different kinds of files: Scenario-Load-Files (.sce) and Run-Result-Files (.run). The Scenario-Load-Files files represent changes that were made to the scenario tree but that were not yet entirely run through IFs software. The Run-Result-Files represent files that were originally changes to the scenario tree that were eventually entirely run through IFs software. The running a Scenario-Load-Files file will make those changes permanent and therefore a Run-Result-File.

In addition to the base case, most versions of IFs will include a number of other previously-run scenarios (see [http://www.du.edu/ifs/help/use/howdoi/lesson0.html Lesson 0] for additional important terminology), perhaps the set of scenarios for the National Intelligence Council’s (NIC) 2020 Project or those for the Global Environmental Outlook (GEO) of the United Nations Environmental Program. If you look, for instance, at the Packaged Display form, you will see a list of previously-run scenarios in the box at the bottom left of the screen. Because those have already been run, based on a set of interventions constituting their foundations, the user can immediately display their results.