Goals
This section contains course syllabus regarding goals. The following should be read and understood in order to create a goal.
Goal
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A goal is a reason why some stakeholder wants this particular system or
function.
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It is a motivation for creating this particular system, not some other system.
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It refers to the target system, not only to other concerns of the stakeholder.
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It may also refer to the domain, market, client, or economic situation, but also to the system.
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It refers to the system as a whole, not to individual features and/or parts of the
systems and their properties.
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Goals shall be reduced to the very core of the argument.
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Express goals as commands (e.g. “make desired media readily available”).
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Goal diagrams will be used to visualize goals and their relationships
later.
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Goals will be used to justify requirements.
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The rationale for any given requirements is to satisfy one or more of the goal.
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Prioritizing requirements may refer to the goals, too.
Relationships Between Goals: Composition
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Many goals are fairly naturally decomposed into sub-goals.
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For instance, when a goal contains generic words like „better“ or refers to
broad quality attributes like „usability“ or „maintainability“ a refinement into
constituents is almost always called for. See e.g. goal G4 before or the ISO
9126 for breaking up quality aspects.
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Example
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Decrease librarians‘ workload
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Support managing LMS effectively
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Automate basic library tasks for librarians
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Provide self-service facilities for readers
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Make using LMS fast and reliable.
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Every goal may be a part of only one other goal.
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If a goal also contributes to another goal besides its immediate super-goal, a
support-relationship may be established.
Relationships Between Goals: Support
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Goals may support many other goals besides their super-goal.
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Goals that do not support any other goals are called top-level goals.
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Example
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Consider three goals A, B, and C.
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A Make desired media readily available.
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B Make media available with little effort.
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C Grant multiple access paths to readers.
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B is part of A, and also supports C, but B is not a part of C.
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There is a fluid line between composition and support
relationships of goals.
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Composition implies support, and often, the two may be exchanged.
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Only strong direct support relationships should be documented.
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Otherwise, goal models approach complete graphs rather soon.
Relationships Between Goals: Obstruction
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There are often conflicts between goals, i.e., satisying one goal
may obstruct the other one.
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Obstruction relationships are often but not always symmetric.
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Example
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Consider two goals A and B as follows.
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A Make media available at little cost.
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B Increase TCL income by increased fees.
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Obviously, there is a conflict between A and B: increased fees for readers will
increase their cost rather than decrease it.
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However, the conflict is not inevitable: if the fees are very small right now,
increasing them makes them bigger, but necessarily big.
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Of course it all hinges on the definition of big and small But that is a decision
course, small. the customer will have to take.
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Defining a conflict does not mean that there is no solution, it just
means that achieving both goals at the same time is not trivial.
Top Level Goals
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Those goals that are not part of another goal are the top level
goals.
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In a goal diagram, they are roots of the composition tree.
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Top level goals justify all the other goals, and thus ultimately, all
requirements: a requirement that does not contribute to a goal is likely to be
unnecessary and wasteful.
Goal Analysis
(note that this version of RED does not support the creation of goal models)
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The process of creating a goal model in a structured and
systematic way is called goal analysis.
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There are several good sources for goals:
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Stakeholder analysis: the stakes of stakeholders are their goals;
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Business process analysis: the process results may be goals;
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Background documents: e.g. the business scenario, or the management
summary;
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Existing requirements: what goal do they serve?
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Other goals: what are their parts? What are they part of? How are they
related?
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Goals can be analyzed systematically and step by step.

Goals vs. Requirements

Describing Goals
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Little differences in the descriptions of goals may have potentially
large impacts on the requirements (and thus the system) they
justify. So, good goal descriptions do matter, and small differences
may actually be quite momentous.
