Difference between revisions of "Decision"
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:The decisions have a special role in causal diagrams, as they list such specific structural parts of variables in a causal diagrams that can be modified by a decision maker. Without a decision, the causal diagram describes the business-as-usual (BAU) situation. A decision variable describes how the situation changes if a decision maker chooses an option over another options of a decision. | :The decisions have a special role in causal diagrams, as they list such specific structural parts of variables in a causal diagrams that can be modified by a decision maker. Without a decision, the causal diagram describes the business-as-usual (BAU) situation. A decision variable describes how the situation changes if a decision maker chooses an option over another options of a decision. | ||
<section end=glossary /> | <section end=glossary /> | ||
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==Question== | ==Question== | ||
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{| {{prettytable}} | {| {{prettytable}} | ||
|+ '''A typical structure of a data table of a decision. | |+ '''A typical structure of a data table of a decision. | ||
| − | ! Decision !! Option !! Variable !! Cell !! Change !! ...!! Value !! Description | + | ! Scenario !! Decision !! Option !! Variable !! Cell !! Change !! ...!! Value !! Description |
|---- | |---- | ||
| − | | A | + | | A group of options that are implemented together and that come from different decisions. |
| + | | A group of options that are exclusive and the choice between them is made by one decision making body. | ||
| An option within one decision. | | An option within one decision. | ||
| A variable whose value is to be changed by the decision option. | | A variable whose value is to be changed by the decision option. | ||
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| This row contains descriptions about columns. The next rows contain examples. | | This row contains descriptions about columns. The next rows contain examples. | ||
|---- | |---- | ||
| + | | Do all | ||
| Energy saving education | | Energy saving education | ||
| Training to house owners | | Training to house owners | ||
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| Energy training leads to renovation of houses and leads to heating demand reduction by 5 %. | | Energy training leads to renovation of houses and leads to heating demand reduction by 5 %. | ||
|} | |} | ||
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| + | ==Rationale== | ||
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| + | Previously, it was thought that decision variables are an essential starting point of a causal diagram, and that they should be general and applicable to all possible situations where that causal diagram is used. Now the thinking is different. Decisions are seen as descriptions of plausible options decision makers have in a particular situation. Decisions are implemented in an assessment as [[scenario]]s (deliberate deviations from the truth, asking: "What would happen if the truth about the decision makers actions was this?"). It was previously also thought that decisions are probability distributions about what a decision maker will decide, and assessment-specific scenarios are used separately to select the interesting options from the decision distribution in a particular assessment. Now the thinking is different: instead of attempting to describe all the decisions, the core of a causal diagram does not describe any decisions. It just describes the phenomena that are important for understanding a situation, such as activities, emissions, exposures, and health effects. Then, decisions are added to that for describing how e.g. activities would change if some decision options would be chosen. In other words, decision variables are used as scenarios. What are scenarios, anyway? | ||
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| + | '''A [[scenario]]''' is a deliberate deviation in a description from the truth. In the case of decisions, it is a particular value of some variable that is changed if the decision option at hand is implemented. It can also be a set of particular values of several variables changed by the decision. For policy assessments, often several scenarios are defined and then compared to each other, e.g. if the impacts of a certain policy (measure) is assessed. A particular set of scenarios can be saved and used in several risk assessments. A scenario therefore can be a part of an assessment but is not an assessment itself. In a sense, BAU is not a scenario, it is our best estimate about what will happen, including all decisions by all decision makers (but typically without explicit lists of these decisions). | ||
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| + | A decision describes changes in values of other variables. These changes must be within the range of values the variable has.{{reslink|Value of the BAU scenario}} | ||
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| + | ==See also== | ||
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| + | ==References== | ||
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| + | <references/> | ||
| + | |||
| + | ==Related files== | ||
| + | |||
| + | {{mfiles}} | ||
Revision as of 13:18, 20 February 2012
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- Decision is a special kind of variable: it answer a question like this: "What are different decisions that decision maker X can make in situation Y, and what are different options of each decision?" Decision maker X may also be a group of distinct decision making bodies, who each can decide about some but not all decisions. In such a situation, an especially interesting part of the related assessment is to look at the interactions of the decisions by different decision making bodies, none of which can fully control the decision situation.
- The decisions have a special role in causal diagrams, as they list such specific structural parts of variables in a causal diagrams that can be modified by a decision maker. Without a decision, the causal diagram describes the business-as-usual (BAU) situation. A decision variable describes how the situation changes if a decision maker chooses an option over another options of a decision.
<section end=glossary />
Question
How should decisions be described in open assessment and what should their structure be?
Answer
| Scenario | Decision | Option | Variable | Cell | Change | ... | Value | Description |
|---|---|---|---|---|---|---|---|---|
| A group of options that are implemented together and that come from different decisions. | A group of options that are exclusive and the choice between them is made by one decision making body. | An option within one decision. | A variable whose value is to be changed by the decision option. | A cell whose value is to be changed within the variable data table. | The type of change. Possible options:
|
The table may also contain other indices. The functions dealing with decision variables use the default merge functionality when combining objects. | The value to be used in the calculations. | This row contains descriptions about columns. The next rows contain examples. |
| Do all | Energy saving education | Training to house owners | Energy balance in Kuopio | Activity:Residential;Fuel:Heat | Relative change | 0.95 | Energy training leads to renovation of houses and leads to heating demand reduction by 5 %. |
Rationale
Previously, it was thought that decision variables are an essential starting point of a causal diagram, and that they should be general and applicable to all possible situations where that causal diagram is used. Now the thinking is different. Decisions are seen as descriptions of plausible options decision makers have in a particular situation. Decisions are implemented in an assessment as scenarios (deliberate deviations from the truth, asking: "What would happen if the truth about the decision makers actions was this?"). It was previously also thought that decisions are probability distributions about what a decision maker will decide, and assessment-specific scenarios are used separately to select the interesting options from the decision distribution in a particular assessment. Now the thinking is different: instead of attempting to describe all the decisions, the core of a causal diagram does not describe any decisions. It just describes the phenomena that are important for understanding a situation, such as activities, emissions, exposures, and health effects. Then, decisions are added to that for describing how e.g. activities would change if some decision options would be chosen. In other words, decision variables are used as scenarios. What are scenarios, anyway?
A scenario is a deliberate deviation in a description from the truth. In the case of decisions, it is a particular value of some variable that is changed if the decision option at hand is implemented. It can also be a set of particular values of several variables changed by the decision. For policy assessments, often several scenarios are defined and then compared to each other, e.g. if the impacts of a certain policy (measure) is assessed. A particular set of scenarios can be saved and used in several risk assessments. A scenario therefore can be a part of an assessment but is not an assessment itself. In a sense, BAU is not a scenario, it is our best estimate about what will happen, including all decisions by all decision makers (but typically without explicit lists of these decisions).
A decision describes changes in values of other variables. These changes must be within the range of values the variable has.R↻
See also
References
Related files
<mfanonymousfilelist></mfanonymousfilelist>
