.. toctree::
.. _DexAnalysis:

Analysis
--------

*Analysis* is one of the key concepts in :ref:`Decision
Analysis <MethDecisionAnalysis>`. In contrast with
:ref:`evaluation <DexEvaluation>`, which is merely a calculation
directed from inputs (data describing alternatives) to
outputs (evaluation results), analysis is understood as an active
involvement of :ref:`participants <Methparticipant>` who are trying to
find answers to questions such as:

-  Are alternative evaluations in accordance with expectations? Are they
   'correct'? If not, why?
-  How do the alternatives compare with each other? Which one is the best and
   why?
-  Can we explain and justify the evaluations? What are the most
   important strong and weak points of individual alternatives?
-  What if something changes: What if we try a new alternative? What if an
   alternative becomes unavailable? What if some alternative's characteristics
   change?
-  How sensitive is the evaluation to small changes of the model (such
   as addition or deletion of an attribute, modification of some
   decision rules)?

In other words, analysis is a creative and possibly repetitive
application of :ref:`DEX models <DexModel>` aimed at better
understanding of the decision problem, better understanding of alternatives,
their characteristics and consequences, and better justification of the
decision. In general, this involves techniques such as: *what-if*
analysis, *sensitivity* analysis, *stability analysis,* etc.

In DEX software, analyses are mostly carried out on the evaluation page,
where the user can:

-  Review intermediate and overall results of evaluation. In
   order to clarify and justify the results, they may focus on
   particularly bad or good evaluations.
-  Change individual alternative values and immediately see the effects on
   evaluation results.
-  Perform other analyses, described below.

Typical analysis operations, implemented in DEX software, include:

- *Selective explanation*:  Identifying particular advantages and disadvantages of an alternative.
- *Compare Alternatives*:  Comparing an alternative with some other alternatives.
- *Plus-Minus Analysis*: Investigating the effects of changing one basic alternative value
  by one or more steps up and down.
- *Target Analysis*: Investigating the changes of multiple basic alternative values that may
  improve or degrade evaluation at some selected attribute.
  
For examples of analyses, see :ref:`Car Evaluation <ExampleCar>` and :ref:`Employee Selection <ExampleEmployee>`.

For more detailed description of analyses, refer to DEX Software: 
`DEXi <https://dex.ijs.si/documentation/DEXi/DEXi.html>`__ and
`DEXiWin <https://dex.ijs.si/documentation/DEXiWin/DEXiWin.html>`__.