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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Adapting new capabilities or enhancing functionality? Two sequence patterns of capability redeem in platform ecosystems</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Philipp Hukal</string-name>
          <email>p.hukal@warwick.ac.uk</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Alexander Eck</string-name>
          <email>alexander.eck@unisg.ch</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>University of St. Gallen Institute of Information Management Unterer Graben 21</institution>
          ,
          <addr-line>9000 St. Gallen</addr-line>
          ,
          <country country="CH">Switzerland</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Warwick Business School - The University of Warwick Information Systems &amp; Management Group Gibbet Hill</institution>
          <addr-line>Road, CV7 4AL Coventry</addr-line>
          ,
          <country country="UK">United Kingdom</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>Platform ecosystem participants often draw from capabilities provided to them by other actors in the ecosystem. While heralded as a driver of innovation, it is unclear how exactly platform evolution is affected by this dynamic. In this short paper we apply event sequence analysis to extract and analyse sequential patterns related to capability redeem - i.e. the internalization and subsequent utilization of external capabilities - on platform ecosystems. We find that development sequences differ in their order of events depending on whether a new capability is being integrated as opposed to the capability being put to use to create novel functionality. In particular, we find evidence for two sequence patterns. First, the platform adapting to new resources and incorporating fresh capabilities, leading to little changes in the functionality of the platform. Second, newly gained capabilities are put to use to enhance platform functionality, incurring substantial adjustments to its external behaviour. Located in information systems research on platform-ecosystems these initial findings present potential for future studies.</p>
      </abstract>
      <kwd-group>
        <kwd>capability redeem</kwd>
        <kwd>digital platforms</kwd>
        <kwd>platform ecosystems</kwd>
        <kwd>sequence analysis</kwd>
        <kwd>openstreetmap</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1 Introduction</title>
      <p>
        Ecosystem dynamics are key in understanding the innovative potential
of digital platforms. Complex interdependencies fuel the continuous,
iterative, and generative manner in which information resources are
recombined across organizational boundaries in order to create digital
innovations [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]–[
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. In attempts to sharpen that view, scholars have
recently combined views on focal and non-focal actors as ecosystem
participants that are not bound to a particular ecosystem, but chose to
interact with a selected ecosystem in order to obtain capabilities [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. A
possible course of action for these actors is to extend their capabilities
through what has been called ‘capability redeem’ [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. Core to this notion
is the idea that ecosystems provide capabilities that are useful in
extending participants’ ability to innovate [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. For example, developers
of a platform could decide to implement authentication of client
applications via a third party protocol such as oauth. With the new
capability implemented, the platform offers the opportunity to its
peripheral actors to develop functionalities that draw from features
requiring authentication and authorisation.
      </p>
      <p>While the literature has explored mechanisms of sharing capabilities
across platform-based ecosystems, it is unclear how exactly the
incorporation and subsequent utilization of ecosystem capabilities plays
out and how changes to platform development can be understood.
Understanding these developments in platform-ecosystems contexts is
important as it would advance the basis for insights on distributed digital
innovations.</p>
      <p>In this short paper, we therefore demonstrate an approach to study the
detailed changes that arise when platforms align their resource base and
incorporate capabilities provided through others in their ecosystem. We
address the research question; What are sequences of events of capability
redeem in platform-ecosystems? Drawing on the notion of capability
redeem, we are particularly interested in the chain of events during the
integration of capabilities to be gained as well as their subsequent
utilisation.</p>
      <p>We present the case of the OpenStreetMap.org (OSM) platform to
answer the above research questions and report initial evidence from a
larger study on platform development. Conceptualising capability
redeem as a two stage process that involves integrating as well as using
the newly gained capability, we identified two focus episodes from the
case. By applying computational event sequence analysis to each
episode, we explicate trajectories of changes to understand how
redeeming ecosystem capabilities influences the development of new
functionality on the OSM platform.</p>
      <p>The remainder of the paper is structured as follows. In the next section
we frame our approach to capability redeem through ecosystem
participation by briefly reviewing relevant literature. We then detail our
approach by highlighting the empirical context as well as event sequence
analysis methods. Finally, we present initial results before concluding
and pointing to opportunities for further research.</p>
    </sec>
    <sec id="sec-2">
      <title>2 Related Work</title>
      <p>
        Co-evolving organisational capabilities through ecosystem
participation is a notion firmly rooted in the information systems
literature [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. One commonly investigated ecosystem topology is that of
a focal actor which – via a central platform – provides shared resources
to a set of connected artefacts owned by non-focal actors. Innovation
capability of a non-focal actor is thought to be a function of how well it
combines shared resources with own assets to generate novelty.
Meanwhile, the focal actor profits from innovations as they grow the
overall ecosystem around the platform as well as the perceived
innovation potential compared to other platforms [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ]–[
        <xref ref-type="bibr" rid="ref7">7</xref>
        ]. IS scholars
offer ample evidence on the benefits actors gain from
platformecosystem participation and how they are actualized (e.g. [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ], [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ]).
      </p>
      <p>
        Considerable work has gone into explicating the mechanisms by
which the exchange of resources and capabilities foster innovation for
participants. For instance, some point out that providing interfaces
facilitates innovation and growth in platform ecosystems [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ]. So-called
boundary resources let the focal actor control what and how resources
are available to non-focal actors. However, far from being unilaterally
controlled, interfaces are subject to complex interaction between focal
and non-focal actors. As reported in [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ], the balancing act of
‘accommodating and resisting’ peripheral interests through shared
resources is crucial for platform innovation. In cases where capabilities
provided to peripheral actors are too limited, the risk of impeding their
innovative capability through ecosystem participation causes tensions.
      </p>
      <p>
        Resolving such tensions is the purpose of governance, which aims to
align detrimental interest between participants. To meet competing
demands, authors have suggested different governance principles [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ].
One such principle is to ensure ‘stability as well as evolvability in
outputs’ (p. 1199) of the ecosystem, with the goal to exercise control
over undesirable variance which shall pave the way for desirable
variance. For example, assuring interoperability with one ecosystem
initially decreases variability, yet in the same time, it also enables
variability in a different part of the platform ecosystem as freed up efforts
can be directed towards innovation.
      </p>
      <p>
        Relevant IS literature advocates benefits of ecosystem participation.
Participants have a clear interest in drawing from capabilities offered
through the ecosystem as far as this advances their ability to innovate [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ].
The pre-condition of aligning and redeeming capabilities is implicit in
the studies, but rarely a topic in its own right. While studies hint at the
necessity to align capabilities in order to innovate, the precise activity
involving capability redeem in order to innovate remains unexplored and
the outcomes undertheorized.
      </p>
      <p>
        For this paper, we draw on the idea of capability redeem [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ] to
understand platform innovation. The perspective provides a solid
framing for our empirical context while affording flexibility for
subsequent theorisation. Additionally, capability redeem is a useful
notion in a number or ways. First, it allows the analysis of platform
activity that is the same time both focal and non-focal to different
ecosystems. Second, it provides a lens on platform capabilities as the
ability to innovate by drawing from a suit of resources provided by
another ecosystem actor. Thirdly, it enables a bi-directional view. That
is, it acknowledges the flow of capability redeem as being gained from
one ecosystem where the actor might be on the periphery and passing it
on to a different ecosystem to which the actor might be core and hence
provides the capability to others. In sum, capability redeem as formulated
in [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ] serves as a theoretical perspective with which to understand an
actor’s innovative ability as a function of redeeming external capability
across digital ecosystems.
      </p>
    </sec>
    <sec id="sec-3">
      <title>3 Research Design</title>
      <p>
        We examine the case of the openstreetmap.org (OSM) platform to
study how capability redeem in a platform ecosystem is unfolding. OSM,
the platform, is an open source software artefact which produces the
assets of OpenStreetMap, the geo-spatial data project, available both via
programmable interfaces and via the browser. In operation since 2004,
‘the Wikipedia of maps’ [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ] is considered the world’s largest
community-driven mapping project on the web with over 3.1 million
registered users who to date contributed a total of 5.4bn geo-spatial data
points1.
      </p>
      <p>OSM is a well-suited case to showcase our empirical approach and
discuss capability redeem in an ecosystem context. Over time, the
platform has been adapted and extended to draw on many technical
solutions provided by other (mostly open source software) projects such
as leaflet.js (a library for interactive maps), Rails (a web development
framework), and Mapnik (a rendering engine). In turn, OSM provides
actors in the OSM ecosystem various capabilities to handle geo-spatial
data. These capabilities are immensely popular and several hundred
commercial and non-commercial web services are drawing from OSM
data and related data handling capabilities in their configurations, for
instance, Craigslist, Wikipedia, and Foursquare2.</p>
      <p>
        The position of OSM as simultaneously a focal actor to its own
ecosystem and non-focal actor in relation to other ecosystems (such as
the ecosystem around leaflet.js, Rails, and Mapnik) presents a fit with
the conceptual perspective on ecosystems proposed by [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. The
perspective offers an initial framing for this showcase without
preempting subsequent avenues for theorisation. Moreover, the OSM case
offers advantages in terms of accessibility. OSM source code is hosted
on GitHub.com to coordinate development work among OSM
developers. GitHub is based on the Git version control system and lets
users share, propose, and discuss software code (cf. [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ], [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ]). In the
case of an open source software project such as OSM, any GitHub user
may openly access its codebase and propose source code changes (‘pull
requests’), in addition to discussing plans and issues on associated online
forums. If a core member of the project agrees with the suggested
changes, the proposal is ‘committed’, or merged with the original code
base and the changes take effect (compare [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ]). Github makes the
content of commits together with a number of metrics publicly available.
      </p>
      <p>To focus the study, we identified a pertinent episode of capability
redeem in the context of OSM that demonstrably resulted in innovation.
Our conceptualisation of capability redeem implies two related yet
distinct streams of activity. First, the addition of the desired capability to
the suite of platform resources. Second, the utilisation of the gained
capability for innovation on the platform.
1 Database statistics as of October 2016,
available at: http://www.openstreetmap.org/stats/data_stats.html
2 http://wiki.openstreetmap.org/wiki/List_of_OSM-based_services</p>
      <p>
        As such we chose the update of Ruby on Rails to version 3.0 and
subsequently version 3.1 as our first episode of interest. As a subsequent
episode of utilisation of newly gained capabilities related to the Rails
update, we chose the extension of the OSM data model with redactions,
i.e. the possibility to prevent the circulation of OSM data objects across
all instances of the OpenStreetMap database. The Rails update episode
and the resulting utilisation of the capabilities gained from it are a
meaningful representation of capability redeem on OSM. The Rails
update 3.0/3.1 focused substantially on the interaction between Rails
components and database operations. Through the set of novel
capabilities OSM was able to react swiftly to two external events that
made adjustments to the platform necessary. First, the inclusion of
redactions as an extension to the OSM data model, protected OSM from
copyright infringement allegations, should data be distributed that
violated intellectual property rights of others. Second, in 2010 the project
underwent a license change from CC-BY-SA3 towards ODbL4 covering
the OpenStreetMap data. This made it necessary to exclude all data
points committed to OSM from distribution for which the new license
agreements have not been accepted by the uploader yet. We
conceptualise these examples as illustrations of our approach while
framing the paper with the conceptual lens that capability redeem
provides. As stated earlier, OSM is dependent on the Rails ecosystem to
provide capabilities needed in operating OSM in its current form [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ].
Rails powers the OSM web application responsible for the OSM website,
application programming interfaces (APIs), as well as other components
such as editors needed to handle geo-spatial data. As such, Rails is
crucial for the OSM platform as it enables a number of key capabilities
that the platform offers to other participants.
3.1 Data
      </p>
      <p>
        We queried the GitHub web API and downloaded all source code
changes committed to the OSM Rails port. Specifically, we focused on
changes made to the ‘rails controllers’. In the Rails architecture,
controllers manage any information processing activity in web
applications (called business logic in other contexts). Controllers
3 Creative Commons Attribution Share Alike
4 Open Data Commons Open Database License (similar to CC-BY-SA, but specifically for data)
coordinate operations between the data model and the various views
presented to the user [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ]. The rails controllers thus present a manageable
subset of OSM development data without sacrificing basis for inference.
      </p>
      <p>
        With the constrains described above we used the downloaded commits
to construct an event sequence dataset [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ], [
        <xref ref-type="bibr" rid="ref20">20</xref>
        ]. Conceptually,
sequences are finite sets of ordered elements such as events, states, or
activities following a temporal, logical, or spatial ordering principle
[
        <xref ref-type="bibr" rid="ref19">19</xref>
        ]–[
        <xref ref-type="bibr" rid="ref22">22</xref>
        ]. Using a quadripartite approach to conceptualise sequential
data structures the following aspects guided data collection and
transformation cf. [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ]–[
        <xref ref-type="bibr" rid="ref21">21</xref>
        ]; (1) the unit of analysis, (2) records of
events, (3) records of activity, and (4) a timeline of observation.
(1) Unit of Analysis: The unit of analyses in this paper are the
temporarily ordered sequences of source code changes committed to
selected OSM components (i.e. rails controllers, hereafter simply
components). This level of detail allows analysis of the changes
made to every single component and was necessary to avoid
inaccuracies. A commit on GitHub often includes several changes at
once and so a single commit may affect multiple components, but
not necessarily to the same effect. In order to increase efficacy of
the sequence method, we analysed each source code change on the
basis of the component it relates to.
(2) Records of Events: Records of events form the first part of bi-modal
data needed to construct sequences. Event sequences typically
represent changes in states of the unit of analysis. For instance, in a
life course study, the event ‘graduation’ changes the state of an
individual from student to graduate. Here we consider every commit
a separate event: Whenever one component was affected by a
commit and hence its source code was changed, we recorded it as
one event. The entirety of commits relating to one component makes
up that component’s development sequence.
      </p>
      <p>Some data transformation was necessary to allow a meaningful
analysis of the collected sequential data. First and foremost, manual
filtering was necessary to eliminate noise that was introduced to the
data by the temporal order of commits. All commits have been
ordered by continuous calendar time based on the timestamps
provided by GitHub metadata5. This consequently implied a relation
5 Note: We use the timestamps the commit was added to the code base (as opposed to when the
commit was authored)
between events (i.e. commits) by virtue of having occurred
immediately before or after one another. This was the case
regardless whether these events are causally related, that is, actually
relating to the same source code issue. Against the backdrop of the
identified episode of capability redeem this required to identify and
derive a subset from the data that contained commits exclusively
referring to the two episodes ‘Rails Update’ and ‘Redaction
Implementation’ respectively.</p>
      <p>
        Filtering of events was informed by the Rails change logs6,7 to
identify potential source code changes relating to aspects of the Rails
update. Prolific changes that guided the data cleaning are detailed in
Table 2. Consequently, the number of all commits associated with
every component was reduced to commits that were clearly
attributable to the ‘Rails Update’ (n = 144) and the ‘Redaction
Implementation’ (m = 37) respectively.
(3) Records of Activity: The second part of bi-modal data for sequence
analysis requires a finite set of mutually-exclusive categories of
activity [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ]. Tracked across time, events are selected from
predefined categories able to qualify what kind of event the unit of
analysis is subjected to. Therefore, the source code changes made to
a component as part of a commit, constitute the activity of the event.
To create a set of possible categories of source code changes, we
classified each commit following the taxonomy of software changes
developed by [
        <xref ref-type="bibr" rid="ref24">24</xref>
        ]. The classes relevant to this study include changes
to the source code base and where applicable changes made to
functionality and external behaviour of the software. In so doing,
we examined each commit and assigned one of the category labels
as described in [
        <xref ref-type="bibr" rid="ref24">24</xref>
        ]. The resulting sequence alphabet for this study
has a size of five elements describing the types of events found in
the data (adaptive, corrective, enhancive, groomative, reductive)8
[
        <xref ref-type="bibr" rid="ref25">25</xref>
        ], [
        <xref ref-type="bibr" rid="ref26">26</xref>
        ]. Table 1 below summarises the applicable classifications,
presents indicators as well as illustrative examples.
6 http://guides.rubyonrails.org/v3.2/3_0_release_notes.html
7 http://guides.rubyonrails.org/v3.2/3_1_release_notes.html
8 Note:
      </p>
      <p>
        Events of type ‘documentation’ were not found in the two focus episodes
Events of types ‘preventive’ and ‘performance’ were omitted from the analysis as they are
effectively unrecognisable without more intimate knowledge of the change process; Also see
[
        <xref ref-type="bibr" rid="ref24">24</xref>
        ] for further details.
      </p>
      <p>Classification was conducted by examining each commit through
the associated URL provided by GitHub, assessing the source code
changes made to every file and deciding on a classification of the
changes. The approach assured that commits changing multiple
components are classified according to the source code changes they
made to each respective component. Ties in classifications were
resolved through discussions with agreement averaging 73.94%
after three iterations of coding.
(4) Timeline of Observation: The rails update 3.0 was initiated on
November 14th 2011. The inclusion of redactions to the data model
began on April 5th 2012. By December 10th 2013, the Rails Port was
once again updated to Rails 4.16, marking the end point of this
study’s observational timeline. To showcase our approach, we hence
only consider events that have taken place in the 25 months between
November 2011 and December 2013. This delimitation allows the
construction of a clear timeline with well-defined start and end
points.</p>
      <p>In sum, the outlined approach resulted in the creation of an event
sequence data set, comprising 27 sequences (19 relating to Rails Update,
8 to Redact Implementation) each representing all relevant change made
to one of the affected components in the time from November 2011 to
December 2013. Figure 1 below presents an illustrative event sequence
with the coded short label for each event type.
Introduction of new APIs for web applications; e.g. Mailer
API for mail notification capabilities provided by Rails
Complementing Active Record methods in database queries
by explicitly supporting AREL function calls in database
handling
Update of xml_to_html requests leads to changes in
javascript pushstate functions used to interact with client
application (e.g. browser history)
Adjustments to CSRF token check now activated by default
and evoked in “app/controllers/application_controller.rb”</p>
      <p>New default javascript framework for AJAX queries in Ruby
3.2 Data Analysis</p>
      <p>
        We use computational event sequence analysis to the filtered, ordered
and coded datasets to study the chain of events occurring in the identified
episodes that we conceptualise as part of capability redeem. We are
specifically interested in the piecemeal steps constituting patterns within
and across sequences. We therefore organised the dataset in an event
sequence structure and aligned sequences by event order. This allows the
time agnostic analysis of individual events and prioritises the
investigation of event order, shared sub-sequences and common event
transitions over duration and timing of events [
        <xref ref-type="bibr" rid="ref20">20</xref>
        ]. In what follows we
present our approach that uses the R package ‘TraMineR’. Aimed at the
analysis of sequence data in the social sciences, ‘TraMineR’ provides a
range of functions for statistical programming in R9 [
        <xref ref-type="bibr" rid="ref27">27</xref>
        ].
      </p>
      <p>Two questions guide the analysis of the development sequences; First,
do sub-sequence patterns differ across episodes? Second, what
wholesequence patterns are characteristic for each respective episode?</p>
      <p>
        First, we extracted discriminant sub-sequences following an approach
described in [
        <xref ref-type="bibr" rid="ref20">20</xref>
        ]. The approach searches for frequent items in an ordered
set. Initial inspection of our dataset shows that sequences are of unequal
length with a maximum of 18 and a minimum of 3 events per sequence
(mean: 6.7; median: 5.0; SD: 4.38). Rooted in the empirical context and
informed by our research focus, we therefore defined five search
parameters which determined what and how many sub-sequences are to
be included for analysis (for details see [
        <xref ref-type="bibr" rid="ref20">20</xref>
        ]).
(1) Start of sub-sequence: To include as many sequences as possible in
the analysis, we limit the event position by which each sub-sequence
has to have started to the second event. Given the minimal sequence
length of some sequences in the set, this would still yield
subsequences of length two with one transition between events.
(2) Length of sub-sequence: With no possible a priori assumptions
about expected sequences, the minimum sub-sequence length of
interest is two events. Since we are interested in maximising the
sample of possible sequences to describe each episode, this results
in the inclusion of every possible event transition.
9 All data collection, transformation and analysis is done using R version 3.3.1; see R Core Team
(2016). R: A language and environment for statistical computing. R Foundation for Statistical
Computing, Vienna, Austria. (https://www.R-project.org/)
(3) Spread of sub-sequence: Similar to (2), we do not restrict the
maximum length of a sub-sequence (i.e. number of events) or the
time window in which it has to be completed, meaning that a
subsequence is counted even if it is interrupted by another event.
(4) Overlap of sub-sequence: We include overlap of spells so that a
subsequence is counted if a meaningful transition occurs multiple times
in varying time windows as long as (1) is observed (for details see
[
        <xref ref-type="bibr" rid="ref20">20</xref>
        ]).
(5) Support of sub-sequence: Every subsequence that occurred at least
once, conditional on (1).
      </p>
      <p>
        The second stage of the analysis is concerned with the derivation of
representative whole sequence patterns in each episode. To that end, we
apply optimal matching analysis to the whole sequences. Albeit nascent
in social science research, optimal matching is an established approach
to dealing with sequential data with prominent applications in sociology
and origins in biology [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ], [
        <xref ref-type="bibr" rid="ref28">28</xref>
        ], [
        <xref ref-type="bibr" rid="ref29">29</xref>
        ]. Generally, optimal matching
refers to techniques aimed at measuring the similarity of diverse kinds of
ordered data. In event sequence analysis, this is achieved by aligning the
data such that each sequence element position in one sequence aligns
with the respective element position of the next sequence. Irrespective of
the exact time point of an event this explicates the order in which events
occurred in each sequence.
      </p>
      <p>
        TraMineR uses the established ‘Needleman–Wunsch’ algorithm to
compute a similarity measure for each pair of sequences [
        <xref ref-type="bibr" rid="ref30">30</xref>
        ], [
        <xref ref-type="bibr" rid="ref31">31</xref>
        ].
Needleman–Wunsch tests which arrangement of pre-defined operations
minimises the number of steps needed to transform one sequence into
another. Two basic operations are available to manipulate sequences;
insertion (i.e. adding), and deletion (i.e. excluding) of sequence
elements. Each operation is assigned a cost representing the hypothetical
effort needed to apply an operation to an element. We use the classical
Levenshtein Distance in our analysis. As such, the cost for both
operations is set to one unit, regardless whether a sequence element is
inserted or deleted to align two sequences. Hence, the used similarity
score simply represents the total number of operations needed to
transform sequences.
      </p>
      <p>
        The cost regime is not arbitrary as sequence alignment operations and
their costs are best informed by subject matter expertise and research
context [
        <xref ref-type="bibr" rid="ref31">31</xref>
        ], [
        <xref ref-type="bibr" rid="ref32">32</xref>
        ]. As such, assigning an equal cost to both operations is
reasonable for our study: Lacking information as to what kind of source
code changes to expect from capability redeem activity, no justification
exists for setting varying alignment costs for a priori. For instance,
setting costs based on observed or expected frequencies of events from
the sequence alphabet is unmerited since we have no reason to believe
that any kind of source code change is more or less likely.
      </p>
      <p>
        Applying Needleman-Wunsch with the Levenshtein cost regime yields
a dissimilarity matrix with the minimal similarity scores for each
sequence. Following an approach described by [
        <xref ref-type="bibr" rid="ref33">33</xref>
        ] we normalized the
similarity measures by maximum sequence length, ensuring that
similarity scores are not biased due to varying number of elements in
each sequence.
      </p>
    </sec>
    <sec id="sec-4">
      <title>4 Results</title>
      <p>The results indicate that the sequence of events in each episode differ
substantially. Both, the analysis of sub-sequence elements as well as
representative whole-sequences provide evidence for the existence of
fundamental differences in the sequential patterns of source code
changes in both selected episodes. We report these initial findings
according to the two guiding questions on sub-sequence and
wholesequence differences.</p>
    </sec>
    <sec id="sec-5">
      <title>4.1 Discriminant Sub-Sequence Patterns</title>
      <p>First, we were interested in potential differences in the order of events
in each development episode asking the question: Do sub-sequence
patterns differ across episodes?</p>
      <p>The result from the discriminant sub-sequence analysis clearly
indicate that the two episodes differ in terms of the elements and
subsequences that constitute the chain of events in each episode. Figure 2
below displays the 25 most determinative sub-sequences for each
episode. For reasons of visual accessibility, we only plot sequences with
maximum length of three elements. Given the low average length of
sequences in our sample, this does not present a limitation.</p>
      <p>In general, the events associated with the ‘Rails Update’ episode
predominantly display sub-sequences that begin with an ‘adaptive’ event
(17 of 25), followed by various combinations of the events ‘corrective’,
‘groomative’, or ‘reductive’. The frequency of events of the ‘enhancive’
category (i.e. adding new functionality) are rare in that group (indicated
by the downward direction of the bar representing the sign of the Pearson
residual). Interestingly, no sub-sequence is statistically significant for
this episode (statistical significance refers to chi square test results
between episodes). This indicates that sequence patterns exist in too
great a variety within the episode to be conclusive about what
subsequences are determinative.</p>
      <p>
        In contrast, consider the sub-sequence patterns that characterise the
‘Redaction Implementation’ episode. Here, sub-sequences beginning
with ‘enhancive’ events are not only more frequent (6 of 25), but are also
statistically significant in terms of their chi-square test results (indicated
by the grey shading of bars) [
        <xref ref-type="bibr" rid="ref33">33</xref>
        ]. This indicates that a sequence within
the second episode can be identified through the existence of
subsequence elements of type ‘enhancive’. The patterns in positive and
significant sub-sequences exclusively begin with an ‘enhancive’ event
followed by combinations of ‘corrective’, ‘adaptive’, or ‘groomative’
events.
      </p>
      <p>Sub-sequence elements with ‘adaptive’ events in the beginning or
among the first sequence elements are common across the ‘Rails Update’
episode. In contrast they are less so in the ‘Redaction Implementation’
episode. In fact, two of the sub-sequence spells beginning with an
‘adaptive’ event are negative identifiers. That is, on a .05 significance
level, a sub-sequence can be categorised as not being from the
‘Redaction Implementation’ episode if it contains these patterns.
4.2 Representative Whole-Sequence Patterns</p>
      <p>
        Next, we turn to the analysis results of whole-sequences, asking; What
whole-sequence patterns are representative for each episode? We
therefore used the dissimilarity matrix as described above to derive
sequences of source code changes that are representative of each episode.
We extracted the five sequences from each episode with minimal
dissimilarity scores. These sequences are referred to as representative
sequences as they display cases for which the effort needed to transform
them in any other sequence is lowest [
        <xref ref-type="bibr" rid="ref33">33</xref>
        ]. They are the cases with the
highest degree of resemblance to all other sequences; hence
representative of their set.
      </p>
      <p>Consistent with the analysis of sub-sequence elements, the analysis of
whole sequences confirms the differences of sequence within each
episode. The five most representative sequences in the ‘Rails Update’
episode all start with ‘adaptive’ events, followed by either ‘reductive’ or
‘corrective’ code changes. Only exception to this are two sequences (#4,
#5) exhibiting an event of type ‘enhancive’ later in the sequence.</p>
      <p>The pattern can be interpreted as incorporating external capabilities to
the OSM platform artefact. The source code changes needed to ‘adapt’
to the new capabilities gained from updating Rails initiate the sequences,
while the rest of the development work is characterised by correcting
functions by either fixing or restricting them (‘corrective’ or ‘reductive’
events) or as in one occasion maintaining the appearance or style of the
code base. The top 5 sequences are illustrated in Figure 3 below.
Fig. 3. Top 5 representative development sequences for the Rails 3.0/3.1 Updates per component;
Labels correspond to the coded event types of source code changes; A = Adaptive, C =
Corrective; E = Enhancive; G = Groomative; R = Reductive</p>
      <p>The sequences in the ‘Redaction Implementation’ episode stand in
stark contrast to the ones in the ‘Rails Update’. Here, without exception,
the most representative sequences all begin with an ‘enhancive’ event
indicating the addition of new functionality to respective components.
The sequences proceed with high variety of possible events before
ending with variations of ‘groomative’, ‘corrective’ or ‘adaptive’ events.
As in the analysis of sub-sequence patterns, the event of type ‘reductive’
is absent from this set of sequences. (see Figure 4)</p>
      <p>The pattern can be interpreted as utilizing the newly gained
capabilities by adding new functionality to the artefact. Related to the
introduction of novelty (‘enhancive’ events) is the adjustment of
resources indicated by ‘adaptive’ events. The majority of succeeding
events deals with the aligning existing functionality indicated by
‘corrective’ events as well as maintaining standards in the source code
base as represented by ’groomative’ events. Given the small number of
eight sequences in this episode, the pattern across the five representative
sequences is especially remarkable.</p>
      <p>Fig. 4. Top 5 representative development sequences for the implementation of redaction
resources; Labels correspond to the coded event types of source code changes; A = Adaptive, C
= Corrective; E = Enhancive; G = Groomative; R = Reductive</p>
      <sec id="sec-5-1">
        <title>5 Conclusion</title>
        <p>In summary, the apparent differences in sub-sequence and
wholesequence patterns indicate contrasts in the unfolding event order during
capability redeem affecting platform evolution. The sequences of source
code changes in the ‘Rails Update’ episode consists of events associated
with maintaining of functionality by use of newly available resources
(‘adaptive’ events). This adaptation is followed by dealing with edge
cases, corrections, and restrictions of existing functionalities later in the
development sequence (‘corrective’ and ‘reductive’ events). The
addition of novel functionality is rare in the entire episode as refelcted
by only two elements of type ‘enhancive’ in the representative sequences
in figure 3. This is unsurprising, given that the alignment of the resource
base through interaction with an ecosystem such as Rails entails
adjusting the resources needed to perform functionality. From the
perspective of capability redeem, OSM is a non-focal actor which needs
to accommodate changes in the Rails ecosystem to keep profiting from
redeeming capabilities from Rails.</p>
        <p>Conversely, the ‘Redaction Implementation’ episode is characterised
by numerous additions of new functionality, followed by aligning
resources as well as tending to maintainability of source code. This is
evident from the prevalence of ‘enhancive’ events in the beginning of
the representative sequences followed by combinations of ‘corrective’,
‘groomative’, and ‘adaptive’ events (compate figure 4).</p>
        <p>Evidence from the ‘Rails Update’ episode of integrating capabilities
gained from an ecosystem partner does not support conclusive
statements at this point. None of the sub-sequence patterns are
significantly different from the sequences contained in the second
episode. While revealing interesting descriptions of the source code
changes entailed in the integration of redeemed capabilities, this
highlights a need for further investigation. Contrarily, the episode
dealing with the utilisation of newly gained capabilities from ecosystem
partners by implementing a new feature, offers promising avenues for
further research. Implicit in the sequence of source code changes
associated with the second episode is the notion that the inclusion of
novel functionalities alters the external behaviour of the software. While
not surprising in itself, this idea invites reflections about how the
evolution of platform-ecosystems is affected by redeeming capability
from ecosystem actors. The OSM platform clearly benefits from
integrating capabilities and resources provided by the Rails ecosystem.
While not advancing functionality of OSM software immediately during
the implementation, our evidence suggests that subsequent design of
novel functionality is substantially affected by the capabilities OSM
developers gained by aligning with updated Rails resources.</p>
        <p>
          Several avenues for further research on platform-ecosystems are
possible based on initial insights showcased here. First, a perspective on
digital innovation through path constitution theory ([
          <xref ref-type="bibr" rid="ref34">34</xref>
          ], [
          <xref ref-type="bibr" rid="ref35">35</xref>
          ]) may be
connected with our findings. Key to the development of digital platforms
are capabilities provided through ecosystem dependencies. It thus could
be of great interest to path constitution researchers to investigate how
technology paths are influenced by the tension between design agency
and ecosystem dependencies. To that end, the event sequences presented
here can serve a starting point for further analysis. Regarding individual
commits and their effect on functionality of a platform as a step in a
technology development path might be a promising approach: ‘Emergent
designs’ [
          <xref ref-type="bibr" rid="ref36">36</xref>
          ] can be traced by analysing multiple simultaneous
development sequences on a highly granular level. Sequence analysis as
well as the detailed view on technology development in a platform
context may be intriguing for anyone interested in extending path
theoretic perspectives.
        </p>
        <p>
          Furthermore, questions concerning changing design rules [
          <xref ref-type="bibr" rid="ref37">37</xref>
          ] might
be of interest for platform researchers. Our results indicate that the
sequences of events stemming from ecosystem dependencies have
substantial effect on platform evolution as new functionality is
influenced by capabilities provided by ecosystem actors. Altering the
architecture of digital platforms triggers changes in crucial task and
design structures and thus influences subsequent technological
development and innovation on the platform. The malleability of digital
technology is a matter of course for information systems researchers, but
detailed insights into the minute design changes and trajectories remain
to be theorised and are hence promising for future studies (e.g. [
          <xref ref-type="bibr" rid="ref15">15</xref>
          ],
[
          <xref ref-type="bibr" rid="ref21">21</xref>
          ]).
        </p>
        <p>Lastly, our approach highlights the feasibility of tracking platform
development on the level of individual components. As such,
development sequences can be related to questions of platform
component composition (see [38]). For instance, the time needed for a
component to fully adopt a new functionality change or the rate with
which changes occur in a component present opportunities for
investigations on platform development as a function of the ease with
which its components incorporate changes. Using measures relating to
sequential dynamics would thus allow to derive insights on platform
evolution.</p>
        <p>On a final note, we hope that despite its early stage character, this
paper demonstrates computational sequence analysis as a potentially
fruitful approach for anyone interested in understanding digital
technology development in platform-ecosystem contexts.</p>
      </sec>
      <sec id="sec-5-2">
        <title>Acknowledgments.</title>
        <p>The authors would like to thank two anonymous reviewers as well as the
participants of the Pre-ICIS event ‘8th International Workshop on
Software Ecosystems’ on December 10th in Dublin, Ireland for their
helpful comments on an earlier version of this paper.
Modularity. Cambridge, MA: MIT Press. Cambridge, MA: MIT
Press, 2000.
[38] A. Tiwana, Platform Ecosystems: Aligning Architecture,
Governance, and Strategy. Amsterdam: Morgan Kaufmann,
2014.</p>
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