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Lucienne BlessingUniversité du Luxembourg
Autumn Lecture-Workshop seriesUniversity of Bath, 19 November 2009
Developing a Reference Model:Developing a Reference Model:
the line of argumentation behind your researchthe line of argumentation behind your research
Productreliability
Maintenancecost
Amount of profit
Market share
+
+
_
_
_
[A]
[A]
_
Companyimage
_
_
[A]
[A]
Productreliability
Maintenancecost
Amount of profit
Market share
+
+
_
_
_
[A]
[A]
_
Companyimage
_
_
[A]
[A]
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Reference and Impact modelReference and Impact model
Reference Model: Aim: to clarify and illustrate the main line of argumentation, that
shows the relevance of your research topic and of the factors, that are most suitable to address in order to solve the problem.
represents the current, identified or assumed situation in design
Impact Model Aim: to clarify and illustrate the main line of argumentation, that
shows of your line of attack and the expected effects. represents the expected, improved situation in design,
resulting from the solution to be developed in the research project
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Example projectExample project
Goal:
Improve the reliability of products to improve product performance (increase sales)
Hypothesis:
Timely assessment of reliability increases the chances of improving product reliability and improve product performance
Research question:
Is that true, and how to do that?
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Setting up the Initial Reference ModelSetting up the Initial Reference Model
Determine the initial set of influencing factors thought to be relevant those factors that may be suitable success criteria; the believed links between the factors in the existing as
well as the desired situation, in particular those linked to the success criteria;
Add any related assumptions Represent every statement with two (or more) nodes
and links
Make explicit current understanding and beliefs
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Setting up the Initial Reference ModelSetting up the Initial Reference Model
Start building a network, by linking statements, beliefs.
Improve the reliability of products to improve product performance (increase sales)
Productreliability
Maintenancecost
Amount of profit
Market share
+
+
_
_
_
[A]
[A]
_
Companyimage
_
_
[A]
[A]
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Adding sourcesAdding sources
Source Edges are labelled with the source of the
statement [x] = publication number. [A] = assumption, [E] = experience, [O] = own study.
Contradicting or differing sources are represented using separate edges
Edges can be given a width representing the strength of the relationship
Productreliability
0 0
+_
Use of DfR-methods
[E][A]
Productreliability
0 0
+_[E][A]
Check any link to see the extent to which these have been shown to exist, or can be expected to exist using the evidence available.
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Contradicting sources and additional factorsContradicting sources and additional factors
Productreliability
Customer satisfaction
Market share
++
+
+[1]
Price _
_+0 [2]
Other factors
Other factors
[A]
[1]
[1]+_
Quality of product Quality of
production
__
[1]
Note: Relationships cannot simply be reversed: if high costs lead to reduced sales, this does not imply that low costs lead high sales.
Factors known or expected to influence the network, but
outside the scope of the research project, are added
but with dashed lines,
Contradicting findings are represented by
multiple links between two nodes
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Combinations of factorsCombinations of factors
When two factors, having a particular value, together effect another factor (a statement involving three or more factors) a connecting line between the two edges is added near the affected factor and with a single value near the connecting line.
Productreliability
0
+
Use of DfR-methods
% of project time left
to improve
_Product-
specificity of the method
0_
+
[E][A]
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(iterations between Research Clarification and Descriptive Study I stage)
This is likely to reveal a network of links based on intermediate influencing factors, e.g. “product reliability is linked to product performance, which is one of the factors influencing market share”
Supporting statements (links) related to other influencing factors might be available in literature
Evidence from literature might be incomplete but it can be expected (assumption) that certain factors can be linked
Refining the Reference ModelRefining the Reference Model
Use literature to add relevant links
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CriteriaCriteria
Criteria: desired values of the factor the research project sets out to understand and/or influence as described in the research goal.
A project can have several criteria A criterion can be relative or absolute, qualitative or quantitative Criteria are needed to be able to judge the outcome of the research against the
goals, i.e. whether the goals have been achieved Criteria about the research process are needed, but not considered in the
Reference and Impact Models
Measurable criteria, Criteria linked to the chosen success criteria that can be applied to judge the outcomes of the research given the resources available within the project or programme. The term measurable refers to the possibility of measuring the criteria during the project not to particular types of method.
Success criteria Relate to the ultimate goal to which the research project or programme intends to contribute. These criteria usually reveal the purpose of the research and the eventual, expected contribution to practice.
Select criteria
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Use of DfR-methods
Success Criterion
Productreliability
Customer satisfaction
Market share
+
+
+
+[1]
Price _
_+0 [2]
Other factors
Other factors [A]
[1]
[1] +_
Quality of product
Quality of production
_
_
[1]
Maintenancecost
_
+
+
Warrantycost
+
++
[4]
[3,4]
[3]
+
Operatingcost
+
+
_
[3]
[5]
Measurable Criterion
0+
% of project time left
to improve
_
Product- specificity of DfR- methods
0_+
[E][A]
Key Factor
Reference ModelReference Model
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Initial Impact Model (partial model)Initial Impact Model (partial model)
% of project time elapsed until
detection
Productreliability
Amount of time needed for
development
_[A] +[A]
Assessingreliability
in early designstages
_
_
_
[A]
Other factors
Other factors
Support
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Factors Factors Influencing factor (node) Aspect of the existing (or desired/expected) situation
considered relevant represented as a node Formulated as attribute + element Example: ‘quality of (attribute) problem definition
(element)’. Wrong: ‘Problem definition’ (no attribute) introduces
ambiguity: ‘time spent on problem definition’?, ‘quality of the problem definition’? or ‘knowledge about the source of the problem definition’,? etc.
The attribute determines the link to other factors. Operational definition possible, i.e. should be possible
to be assessed.
Key factor• influencing factor to be addressed by the proposed support. • Example: ‘quality of problem definition’
Quality of problem definition
Attribute
Element
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StatementsStatements
Link Represents the link between factors. ( = directed (causal) link)
quality of product definition
level of customer
satisfaction
Statement
Attribute
Element
Link (causal)
Factor
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StatementsStatements
Existing (or desired/expected) value of an attribute Attached to the links near the factors by means of ‘+’, ‘’, or ‘0’. Example: ‘-‘near factor ‘quality of product’ indicates ‘poor quality’. Ensure that attribute values are unambiguous by precise labelling of the
nodes: “leadtime” is “+” might mean leadtime is positive (i.e. short) or leadtime is long(er). “Amount of leadtime” is less unambiguous.
quality of product
level of customer
satisfaction
+
+
Statement
Value of attributeLink (causal)
Source
[1]
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Determining the need for a detailed Determining the need for a detailed Descriptive StudyDescriptive Study
Based on the gained understanding determine whether sufficient evidence is available to identify the “line of attack” or whether a detailed Descriptive Study is necessary to determine missing links or to verify assumptions.
If a detailed Descriptive Study is necessary: Refine the research problem into research questions or
hypotheses to be addressed in the project.
If sufficient evidence is available Identify the line of attack, i.e. the factors to be addressed in
order to improve the identified situation and to achieve the aim. Start a Prescriptive Study by setting up the Impact Model, to
illustrate the improved situation.
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TaskTask
Develop an initial reference model for your research project
Use a large sheet of paper to present your model If time allows and if relevant for your project,
develop an initial impact model
Good luck and have fun!