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    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Choice Navigation Assessment for Mass Customization Kjeld Nielsen1, Thomas Ditlev Brunoe1, Simon Hahr Storbjerg2</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Kjeld Nielsen</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Thomas Ditlev Brunoe</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Simon Hahr Storbjerg</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Department of Mechanical and Manufacturing Engineering, Aalborg University</institution>
          ,
          <country country="DK">Denmark</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Vestas Wind Systems A/S</institution>
          ,
          <addr-line>Aarhus</addr-line>
          ,
          <country country="DK">Denmark</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2013</year>
      </pub-date>
      <fpage>29</fpage>
      <lpage>30</lpage>
      <abstract>
        <p>In mass customization, the capability Choice Navigation which is defined as the ability to support customers in identifying their own solutions while minimizing the burden of choice, is essential to market high variety product portfolios effectively. We argue that there is a need for methods which can assess a company's choice navigation and their capability to develop it. Through literature study and analysis of choice navigation characteristics a number of metrics are described which can be used for assessment. The metrics are evaluated and analyzed to be applied as KPI's to help MC companies prioritize efforts in business improvement.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>Introduction</title>
      <p>In any company it is essential to offer products which match
the needs and desires of customers in order to achieve sales
and profit. This is the case for mass producers as well as
mass customizers; however in mass customization this issue
is somewhat more complex than mass production due to a
much higher variety and a more complex product structure.
As pointed out by Salvador et al., mass customizers need
three fundamental capabilities to be successful (figure 1): 1)
Solution Space Development – Identifying the attributes
along which customer needs diverge, 2) Robust Process
Design – Reusing or recombining existing organizational
and value chain resources to fulfill a stream of differentiated
customer needs and 3) Choice Navigation – Supporting
customers in identifying their own solutions while
minimizing complexity and the burden of choice [Lyons et
al., 2012; Salvador et al., 2009].</p>
      <p>In order for companies to be able to establish themselves
as mass customizers or for existing mass customizers to
improve performance, it is proposed that a set of methods
for assessing the three capabilities is developed. In this
paper, the focus is solely on the capabilities for Choice
Navigation. The research question for this paper is:
What metrics can be used to assess capabilities for choice
navigation and how can these be determined?</p>
      <p>The research question is addressed by first defining
choice navigation, and in overall terms, which areas should
be assessed. Then a literature review is conducted to
identify existing metrics. These metrics are evaluated in
order to evaluate whetherthey are can be applied to assess
the choice navigation performance, and a final set of metrics
is developed including newly defined metrics.</p>
      <p>Solution</p>
      <p>Space</p>
      <p>Devlopment</p>
      <p>Choice
Navigation</p>
      <p>Robust
Process
Design
Figure 1 The three fundamental capabilities in mass
customization [Salvador et al., 2009]
2</p>
    </sec>
    <sec id="sec-2">
      <title>Choice navigation</title>
      <p>The capability choice navigation is defined by Salvador et
al. [Salvador et al., 2009] as “Support customers in
identifying their own solutions while minimizing
complexity and the burden of choice”. Hence this capability
is related primarily to the capabilities of the configuration
system, and its ability to configure a variety of products.</p>
      <p>Salvador et al. proposes three different approaches to
develop the capabilities within choice navigation:
Assortment Matching, Fast-cycle, trial-and-error learning
and Embedded configuration. However these support the
development of choice navigation rather than the assessment
of choice navigation capabilities.</p>
      <p>Two different perspectives are relevant when assessing a
company’s choice navigation capabilities. The first
perspective addresses the capabilities for supporting the
customer in choosing a product which matches the
customer’s needsfulling. The second perspective is
concerned with how well the choice navigation supports the
business process involved in product configuration. This
paper will focus on the assessment of choice navigation
purely from the customer’s perspective, thus focusing on the
capabilities supporting the customer in the configuration
process.</p>
      <p>The ideal product configurator should after a customer
has finished a configuration leave the customer with the
experience that the process has not been unnecessarily
difficult to perform and the customer has been able to match
his or her needs exactly to a specific configuration of a
product [Salvador et al., 2009].</p>
      <p>Supporting the customer in the configuration process,
thereby making the product configuration task easy and fast,
is a matter of aiding the customer in matching
characteristics of needs, empowering customers in building
models of needs or embedding the configuration in the
product itself [Salvador et al., 2009]. Measuring how well
choice navigation in a specific company ensures a 100% fit
between customer needs and the goods configured by the
customers is a somewhat difficult task.</p>
      <p>Solution Space (SS)</p>
      <p>Customer Demanded Variety</p>
      <p>(CDV)
SS</p>
      <p>SS ∩ CDV</p>
      <p>CDV</p>
      <p>The problem of assessing the fit between customer needs
and a configured product can be described using set theory.
Since the objective of choice navigation is to match the
customer demand with the offered solution space, a set is
defined for each of these as illustrated in figure 2. The
optimality of a solution space can then be described by
defining two sets of products: 1) the different products
offered by an MC company, defined as the set SS (Solution
Space) and 2) the variety of products which are demanded
by the customers, defined as the set CDV (Customer
demanded variety). As illustrated in figure 1, the
intersection of the two sets will represent the products
offered by the MC company which correspond to products
demanded by customers. The intersection of the two sets
thus represents the products that customers may buy, given
they are able to find and configure the products and willing
to pay the required sales price.</p>
      <p>Intuitively, maximizing the set SS∩CDV would seem like
a good idea since this would maximize the potential number
of product variants that can be sold to customers. It would
also seem intuitive that the set SS \ CDV i.e. products which
are part of the offered variety but are not demanded by
customers should be minimized or even eliminated.</p>
      <p>When describing these sets, it should be defined which
elements are in the set or in other words. What is an
element? One possibility would be that each element in the
sets corresponds to a unique product variant. Following this,
each possible combination of configuration choices would
correspond to a variant and thus an element in the set.
However, for most MC product families, the number of
elements becomes astronomical due to numerous
configuration variables each with a number of outcomes.
For example, when configuring a Mini Cooper online the
configuration choices presented to the customer will result
in a number of possible variants well above a 20 digit
figure. This is obviously significantly more than the
potential market of the Mini Cooper. Assuming that the sale
of Mini Coopers is a good representation of the demanded
variety, and the Mini Cooper has sold a few million cars and
assuming that each sold Mini Cooper is unique, the
customer demanded variety will only be a tiny fraction of
the offered variety and as a consequence. Furthermore we
would expect that assessing whether single variants would
counter a demand from a customer is simply not possible if
the number of variants is high. Thus it would seem that
variants defined as all possible combinations of
configuration variables is not an appropriate way to define
the solution space set as well as assessing the intersection of
SS and CDV.</p>
      <p>A more simple and comprehensible way of representing
the sets may be defining the elements of the sets as the
“dimensions of customization”. If a product has a number of
customizable attributes and each attribute has a finite
number of values that can be chosen, each value will
correspond to a product property which can potentially be
demanded by a customer.</p>
      <p>We thus propose that the solution space is described by
the number of customizable attribute’s values. For example
if a product can be configured in two different sizes and ten
different colors, the SS set will contain 12 elements; two
size elements and ten color elements. Defining the solution
space this way is trivial, since an MC company’s offerings
will usually be explicit in a configurator, product family
model or other documentation. Defining the set CDV on the
other hand is far more difficult since it will be impossible or
at least extremely time consuming to clarify all potential
customers’ demand for variety. Also this would depend on
the delimitation of the product family’s intended customer
base. As a result, measuring the size of CDV will
expectedly be practically impossible. The intersection of SS
and CDV however only describes which products match the
demand of customers, and not whether the customers
actually buy the products. Whether the customers buy the
products is a matter of several other factors; however the
first obstacle is whether the customers are able to match the
needs with an actual product configuration, which is the
essence of choice navigation. For this reason, we introduce
another set, Customer Configuration (CC), which contains
the variety that is actually being configured by customers.</p>
      <p>The Set CC intersects with both SS and CDV as shown in
figure 2, and intuitively the intersection of all three sets
SS∩CDV∩CC indicates the optimal situation, where the
solution space satisfies a customer demand and the customer
is able to configure the product. Conversely, all variety not
contained in SS∩CDV∩CC could indicate a problem.</p>
      <p>Solution
Space (SS)</p>
      <p>B</p>
      <p>G</p>
      <p>E</p>
      <p>A</p>
      <p>D</p>
      <p>C
F</p>
      <p>Customer
Demanded
Variety (CDV)</p>
      <p>Customer
Configuration (CC)</p>
      <p>Analyzing figure 3, intersections B and C are
consequences of a mismatch between the actual demand and
solution space, where B implies variety which is part of the
solution space but has no demand thus potentially implying
unnecessary complexity costs. C implies a demand for
variety that is not met by the current solution space and
which may indicate an intersection where the development
of the solution space could increase sales. The D
intersection is seemingly less interesting in terms of choice
navigation, since they relate primarily to the capabilities
within solution space development.</p>
      <p>In intersection D the customer configures a product that
does not meet the demand nor is it contained in the solution
space. This is not a typical situation but is nevertheless
undesirable, and would likely be indicated by the customer
abandoning the configuration. In intersection E, there is a
match between the variety offered by the company and the
customer demand; however the customer does not configure
the product. This is likely a result of a user interface unable
to guide the customer satisfactory through the configuration
process. Intersection F indicates configuration which match
a customer demand, but is outside the actual solution space,
i.e. a product that can be configured but not produced,
which is also highly undesirable. Finally, in intersection G
the customer configures a product that is within the solution
space but does not meet the demand thus resulting in a
customer disappointment.</p>
      <p>The description of the sets CC, CDV and SS above will
be used in the following as criteria for evaluating and
developing different metrics used for assessing choice
navigation capabilities, since metrics indicating variety
outside SS∩CDV∩CC will indicate sub optimality within
choice navigation.</p>
      <p>When assessing a companys capabilities within choice
navigation it must be considered within which kind of
business environment the configuration will be done. There
is typically a great difference in choice navigation setups
depending on whether the sales process is done in a business
to business (B2B) or in a business to consumer (B2C) sales
process. Both setups can be assessed using the same choice
navigation metrics, however there are typically differences
in the sales setups, where in B2B it is often the sales
organization performing the actual configuration process,
whereas in B2C this is typically performed by the end
customers. Due to this difference, assessessment metrics for
choice navigation should be investigated for bias or
benchmarking issues when using the results across the
different business environments B2B and B2C. We will in
this paper not these differences further.</p>
      <p>Choice Navigation metrics representing time and effort to
reach a configuration, should ideally be developed so that
all assessment results could be benchmarked against each
other. However regocnising differences between different
products and business setups, the metrics should at least
allow for benchmarking within a product type and business
environment.</p>
      <p>One example where differences in product types could
make benchmarking between different products non
representative is where customers have a great interest in the
product and actually wish to spend long time on the
configuration process making it more than an experience
than a transaction. In this case, a metric indicating high
performance for shorter configuration processes might not
be representative for the goal the configurator is designed to
achieve. Hence, each metric should be scrutinized in
relation to assessing a specific product, as special
considerations might be relevant for special products.
3</p>
    </sec>
    <sec id="sec-3">
      <title>Literature review</title>
      <p>Blecker et al. identified and developed a number of metrics
for varity steering [Blecker et al., 2003]. Some these metrics
are relevant for assessment of choice navigation, and these
are identified in the following along with other relevant
metrics from literature.</p>
      <p>Average configuration length of time metric (CT)
∑
source: [Blecker et al., 2003]</p>
      <p>This metric measures how long time a customer or sales
person uses for performning the acutal configuration process
Configuration abortion rate metric (CA)
source: [Blecker et al., 2003]</p>
      <p>The CA metric describes how frequently customers or
sales people choose to abort a configuraiton which has been
initiated due to whatever reason.</p>
      <p>Customers Return Rate metric (RTR)
source: [Piller, 2002]</p>
      <p>The RTR metric describes how often customers returns a
product to the company after receiving it due to e.g.
disappointment in the product.</p>
      <p>Customers Churn Rate metric (CR)
source: [Sterne, 2003]</p>
      <p>The CR metric describes the relationship between new
customers and lost customers.</p>
      <p>Customers Repurchase Rate metric (RR)
source: [Piller, 2002]</p>
      <p>The RR metric describes how often products are
repurchased, or how often customers return to byt another
different product.</p>
      <p>Customers Complaints Rate metric (COR)
source: [Blecker et al., 2003]</p>
      <p>Similar to the CR metric, the COR metric describes how
often customers complain over a product they have
purchased after receiving it.</p>
      <p>Walcher and Piller conducted a survey of 500 different
mass customization companies, and for this purpose they
developed a number of metrics for comparing the different
mass customizers [Walcher &amp; Piller, 2012]. The analysis
focused primarily on the configurators, i.e. choice
navigation but also on the products. Four objective metrics
were included:
 Visual features – To what extent the product is
visualized as it is configured, e.g. 2D picture,
multuple views, Zoom etc.
 Navigation help – Whether help like progress bars,
activity lists, option to save etc. is provided

</p>
      <p>Company help – Whether help like
recommendations, deeper explanations, design
examples etc. is present
Customer help – Whether users of the configurator
is able to get help or inspiration from other users
directly or indirectly.</p>
      <p>The metrics were evaluated on a scale from 0-4
representing how many of the elements were found in each
configurator.</p>
      <p>Furthermore, evaluators which were independent mass
customization experts were asked to evaluate each
configurator using the following subjective metrics:
 Visual realism
 Usability
 Creativity
 Enjoyment
 Uniqueness
 Choice options</p>
      <p>Each metric consisted of a number of sub-metrics which
the evaluators were asked to assign a rating between 1 and
5. Each configurator was evaluated by 3 different experts
and an average was calculated for each metric for each
configurator.
4</p>
    </sec>
    <sec id="sec-4">
      <title>Choice navigation metrics</title>
      <p>In order to evaluate which metrics are usable for evaluating
choice navigation capabilities, the different set intersections
illustrated in figure 2 are addressed individually. For each
intersection, it is evaluated which metrics can support the
assessment.</p>
      <p>Another requirement for the metrics is that they should be
measurable based on readily available data in a company’s
IT systems, i.e. ERP, CRM, PLM and configuration
systems, since this would allow mass customizers to utilize
these metrics for continous improvement.</p>
      <p>Please note that intersections B and C are disregarded in
this context since they relate more to capabilities within
solution space development than choice navigation.</p>
    </sec>
    <sec id="sec-5">
      <title>4.1 Intersection E</title>
      <p>In this case, the customer will start to configure a product,
but never reach a final configuration which is purchased,
although the solution space supports the requirements. This
is difficult to distinguish from the case where requirements
cannot be met within the existing solution space
(intersection C), however high CA metric can be used as an
indication since customers that cannot configure a product
to meet their requirements will likely abandon the
configuration.</p>
      <p>Furthermore, if configurations utilise only a small portion
of the solution space and if many configuration variables,
rarely deviate from the default values, that may indicate that
customers are not aware of all possible variety and have
therefore not been able to configure a suitable product
although it is in fact offered.</p>
    </sec>
    <sec id="sec-6">
      <title>4.2 Intersection F</title>
      <p>In this case, customers configure products which are within
the customer demanded variety but outside the solution
space, i.e. a product is configured which cannot be
delivered. This would likely result in the order being
cancelled by the company, since it cannot be manufactured.
Alternatively, the company will change the configuration to
fit within the solution space by e.g. upgrading the product.
As an indicator for these configurations we introduce two
new metrics:</p>
      <p>Seller Order Cancellation rate (SOCR)
Seller Order change rate after purchase (SOCRAP)
High values of SOCR and SOCRAP would then indicate
configurations within intersection F.</p>
      <p>Configurations within intersection F as well as D would
be a result of a faulty implementation of a configurator,
since a configurator should ideally reflect the company’s
solution space or a subset of the solution space. Reaching
configurations within intersection F and D is very
undesirable, since it will lead to loss of credibility as well as
a need for costly manual business processes to resolve the
issue.</p>
    </sec>
    <sec id="sec-7">
      <title>4.3 Intersection G</title>
      <p>In this case, the customer configures a product which is
within solution space but does not correspond to the
customer’s requirements. In this case several things could
happen. If the customer realises that the product is not
satisfactory prior to delivery, the customer may cancel the
order or change the configuration. To indicate this, two new
metrics are introduced:</p>
      <p>Customer Order Cancellation rate (COCR)
Customer Order change rate after purchase (COCRAP)
In other cases, customers will not realise that the
configured product does not meet requirements, until it is
received. In this case the customer may return the product
(indicated by RTR) or complain (indicated by COR). Also
repurchase rates (RR) and churn rates (CR) would be
affected.</p>
      <p>Hence configurations within intersection G would be
indicated by high values of COCR, COCRAP, RTR and
COR and CR and low values of RR.</p>
    </sec>
    <sec id="sec-8">
      <title>4.4 Intersection D</title>
      <p>In this intersection, the customer configures a product with
properties that the customer does not have a demand for and
is not part of the solution space. In this case either the
customer or the company can react to this and either cancel
or change the order. Hence configurations in intersection D
will be indicated by High values of SOCR, SOCRAP,
COCR and COCRAP. It may however be difficult to
determine whether high values of SOCR and SOCRAP are
due to configurations in intersection D or F. On the other
hand, the customer does not receive the product no matter
which are the configuration is in, so whether the customer
had a demand for the product may be less important.</p>
    </sec>
    <sec id="sec-9">
      <title>4.5 Intersection A</title>
      <p>Basically, sales within intersection A are the optimal
solution, since products are sold within the solution space
which also match the customers’ requirements. Hence if
there is little indication of configurations outside
intersection A, then that should indicate that configurations
are within intersection A. Since configurations within
intersection A should lead to a sale, then an increase in CSR
would also indicate an increase in configurations within
intersection A.</p>
      <p>Configuration sales rate metric(CSR)</p>
    </sec>
    <sec id="sec-10">
      <title>4.6 Further metrics</title>
      <p>Apart from the metrics which relate directly to the
intersections A-G, we identified a number of metrics which
may be used to explain why configurations occur in
intersections outside intersection A. Hence the metrics can
be used to explain the possible reasons for a problem with a
configuration system rather than whether there is in fact a
problem.</p>
      <p>Configuration click index metrics(CI)</p>
      <p>∑</p>
      <p>CI metric is a measure of the number of selections,
choices or clicks the customer makes in the configurator; or
in other words the effort needed by the customer for
performing the configuration. It could be the number of
selections or actions which the customer has made for a
number of given configurations indexed with the total
number of variables available in the configurator. The
metric cannot be used as benchmark in general or as
comparison to other companies/configurators but it can be
used internally as an indicator for how a change due to
implementation of new variables in the configurator or
change of configurator has impacted the choice navigation
performance. Increase of CI may indicate more complex
choice navigation or an increase in burden of choice
navigation. In a broad view it can be argued that a a value of
CI at or near one may indicate a perfect choice navigation.</p>
      <p>Time used in configuration index metric(TI)</p>
      <p>∑</p>
      <p>As for CI the TI metrics gives an index of the time used
for a number of given configurations. As for CI the TI may
be used internally as an indication of change in burden of
choice caused by change of variables and/or change of
configurator.</p>
      <p>Some of the metrics defined in MC500[Walcher &amp; Piller,
2011] can also be utilized as metrics in this context.
However only the objective metrics are included here, and
thereby not the metrics that are based on a subjective
evaluation. The included metrics are:
 Visual features
 Navigation help
 Company help
 Customer help</p>
      <p>All of these metrics are indicators of how customers are
guided or helped through the configuration process. Given a
company finds that many configurations are observed in
intersections E or G, then looking into these metrics may
explain the reasons for this.
5</p>
    </sec>
    <sec id="sec-11">
      <title>Conclusion &amp; Dicsussion</title>
      <p>In order to support the development of choice navigation in
mass customization and thereby also product configuration,
metrics are needed in order to assess the choice navigation
performance. To establish these metrics, relevant literature
was reviewed and several applicable metrics were
identified. Further metrics were defined in areas where no
sufficient metrics could be identified in literature. The
following list compiles the metrics identified in literature
and newly defined metrics within choice navigation:
Metrics identified in the literature
 Configuration abortion rate metric (CA)
 Customers Return Rate metric (RTR)
 Customers Churn Rate metric (CR)
 Customers Repurchase Rate metric (RR)
 Customers Complaints Rate metric (COR)
Newly defined metrics
 Seller Order Cancellation rate (SOCR)
 Seller Order change rate after purchase
(SOCRAP)
 Customer Order Cancellation rate (COCR)
 Customer Order change rate after purchase
(COCRAP)
 Configuration sales rate metric(CSR)
It is the intention that these metrics can be used in MC
companies for different purposes. One purpose is
benchmarking against “best practice” mass customizers, in
order to identify areas with the greatest potential for
improvement. Another purpose is to use these metrics as
key performance indicators which are continually calculated
to monitor performance to continuously improve. In relation
to research in mass customization it is the intention to apply
these metrics in different types of mass customization
companies to analyze what distinguishes successful mass
customizers.</p>
      <p>It is evident that the application of these metrics poses
certain requirements related to data availability and quality.
However, most MC companies already have systems in
place which are very likely to contain the data required for
calculating the metrics presented in this paper.</p>
      <p>As mentioned in the introduction, choice navigation is
one of three fundamental capabilities for successful mass
customizers; the other two being robust process design and
solution space development. There are strong relations
between these three capabilities, and phenomena
experienced in a company cannot necessarily be attributed
to only one capability, and as such, the metrics defined in
this paper can also be influenced by other factors than the
solution space development capability.</p>
      <p>One example is the metric configuration abortion rate
which we argue indicates how well choice navigation is
implemented. However, the configuration abortion rate will
be strongly influenced by the solution space, i.e. how well
the offered variety matches the demanded variety. The value
of this metric can thus both be influenced by a company’s
performance within choice navigation as well as solution
space development. In future research, metrics for the other
two capabilities, Robust Process Design and Solution Space
Development should be established and the links between
all three capabilities can be analyzed. Furthermore, the
relations between metrics performance and specific methods
should be addressed so that an assessment could point out
not only what a company should do to improve but also
how.</p>
      <p>When performing an assessment and interpreting the
values of the metrics, the interpretation should take into
account the product type. Also when benchmarking,
different products cannot necessarily be compared directly.
The reason for this is that several metrics are based on the
customers actions, and these actions will depend on the
product type. For exampe if a customer buys a customized
car compared to a customized bag of muesli, then the
customer would probably be more likely to complain or
return the car if it has a wrong color compared to the muesli,
if a wrong ingredient has been added. In that case, the
difference would be due to the dfference in cost of the
products. Furthermore a metric like the repurchase rate
makes more sense for some product types than others. For
example, customers are likely to repurchase muesli more
often than cars. So this metric would depend on to what
extent a product can be characterised as a consumable or a
durable, and in case it is a durable, how long the life cycle
is.</p>
      <p>With this paper we have ended a preliminary research of
assessment and measurement of the mass customization
process. We have with this paper finalized a general
approach describing how to assess and measure mass
customizatioin and developed a framework of potential
metrics useful for assessment and measurement of mass
customization, whether this is for the purpose of internal
performance indicators or it is used for benchmarking in
general. Next phase in this research will be test and
evaluation of the metrics.</p>
    </sec>
  </body>
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