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resaerch 7

Designing Assessment Tools in a Service Oriented Architecture
Will M Davies and Hugh C Davis
Learning Technologies Group, ECS, University of Southampton, Southampton, UK
{wmd04r|hcd}@ecs.soton.ac.uk
Assessment is an important component of formal learning, and Computer Assisted Assessment (CAA) is
a well established component of most online learning. However, technical issues such as
interoperability and security, and pedagogic reservations as to its effectiveness still remain barriers to
the uptake of CAA. In this paper we examine a number of current assessment projects, predominantly
emanating from the UK, to consider how a service oriented architecture can facilitate the
implementation of tailored assessment environments, providing improved assessments within an
interoperable and secure framework.
1. INTRODUCTION
The ELeGI [8] project is concerned with building an infrastructure to support all forms of learning, both formal and
informal. Assessment is concerned with measuring progress in learning, and may be used by institutions, such as
Schools, Universities and Professional Bodies, to inform themselves of the progress of a learner (we call this
summative assessment), or assessment may be used by the learners themselves in order to measure and confirm
their own progress (we call this formative assessment). Either way, the assessment is generally of concern to the
formal learning domain, where a learner has clearly defined learning targets against which they are being
measured or measuring themselves.
Because of the importance of assessment within formal learning environments, and the difficulty that teachers
experience in finding time to mark and give feedback on all of a learner’s work, Computer Aided Assessment has
been an active research area within learning technology for many years, dating back to the use of punch cards.
More recently web based educational systems have provided the channel to allow easy access, any time, any
where to Computer Aided Assessment (CAA) servers.
Such CAA systems have generally been stand-alone, often bespoke developed and lock content inside proprietary
systems. Until recently institutions had a choice between the one size fits all, monolithic commercial offerings,
developing their own or customizing someone else’s bespoke application. This approach has constrained the
ability for new systems to leverage developments in previous ones.
Probably the most significant commercial systems in general use are Question Mark Perception [18] and the
assessment tools within learning management systems such as WebCT™ and Blackboard™; these are capable of
delivering summative assessments to large classes but are constrained in both their functionality and
interoperability. Whilst the capability of these systems has increased over time, for commercial reasons they tend
to follow rather than lead development in CAA.
The educational establishments in which CAAs are deployed are likely to contain a large number of innovative
thinkers, it tends to be these people that drive development to better serve their institution’s educational needs. It
is likely that the nature of these, technology early adopters, has led to them developing custom systems as they
have found this more productive than requesting features from commercial suppliers. Because of the diverse
requirements of systems and limited funding, these developments have usually resulted in systems that have poor
interoperability and do not fit the requirements of a broad enough user base to ensure widespread uptake and
continued development.
One criticism of CAA is that it is difficult to assess higher order skills (evaluative skills, design skills, synthesis skills
etc.) using objectives tests, such as multiple choice and true/false questions. This issue has been addressed by
Duke-Williams and King [6] who have successfully used objective tests to achieve this goal, though they do stress
the high level of care that must be taken when creating such tests.
Two alternative approaches to assessing higher order skills are free text marking systems and TRIADS. TRIADS
[15] is an assessment creation and delivery system developed at the University of Derby, UK, which allows the
author to design complex scenarios, simulations and activities for learners, and to intelligently sequence users
through sets of questions, allowing for a very wide and flexible range of question types. With the more recent
development of the IMS Global Learning Consortium’s Question and Test Interoperability (QTI) [9] specification,
this flexibility has become a trade-off against the widespread interoperability that QTI is expected to bring.
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When it comes to marking free text and essays, systems such as Automark [16] and E-Rater [17] are making good
progress at marking both writing style and content. Such systems have been demonstrated to be just as reliable
as human markers, but have yet to gain acceptance within the educational community.
As the mechanisms for building loosely coupled systems from components become more sophisticated the ability
to assemble a complete assessment system from services and integrate this inside a Virtual Learning Environment
(VLE) is becoming possible. A Service Orientated Architecture (SOA) will facilitate the rapid development of highly
customizable systems that can be optimized towards a specific goal or pedagogical requirement. This framework
will also make it easy to plug in extra components or combine services in novel ways to evaluate their
effectiveness.
2. STANDARDS AND INTEROPERABILITY
The development of questions and exercises suitable for computer aided assessment is a time consuming
business and teachers who have invested time in this endeavour have often been frustrated to find that questions
prepared for one system cannot be transferred to another. For this reason the IMS consortium have directed much
effort towards the production of an interoperable specification for questions and tests.
QTI describes a data model to represent questions, responses, marking, results and aggregation of assessment
items to form tests, and thus allows the sharing of objective tests between different organizations and software
environments. The specification is implemented in an XML schema that allows for the exchange of items and tests
between heterogeneous assessment systems.
Application developers are becoming increasingly aware that they cannot rely on a homogeneous environment in
which to deploy their application. In a SOA this concept is taken one step further by combining a number of
heterogeneous subsystems. In this environment the protocols used to communicate and the interfaces between
the systems become increasingly important and must be clearly defined. Clearly any SOA that handles objective
assessments must have a common method of describing these assessments.
The main benefits of using QTI are interoperability, integration, banking and, potentially, wide pedagogical support.
The ability to include QTI described questions seamlessly alongside other learning resources inside a single
integrated environment can avoid the need for students to log in and out of disparate systems and allow formative
assessment to be presented in conjunction with other learning resources. The use of QTI in a SOA increases the
options for embedding assessments alongside other learning components. Using searchable test banks to store
and share questions simplifies the re-use of assessments and tests, though this still requires a degree of
cooperation on how the question metadata should be used.
There are potential problems associated with insisting on adherence to QTI; doing this may cause situations where
the technology, rather than the pedagogical requirement, determines the way in which students are assessed. The
QTI specification is still relatively young, even though version two has undergone an extensive public draft
consultation phase it would be surprising if there were not still some inconsistencies in it. The QTI specification is
large; to be QTI compliant a system must be able to interpret and render correctly a number of complex question
types that may be unnecessary for the environment in which the player is used. The problem is mitigated inside a
SOA where an individual service will be able to state its level of conformance to the specification.
Adherence of assessment systems to the QTI specification is so far limited. Commercial systems such as Question
Mark and Blackboard have made attempts to track the evolution of the specification, at least as an import/export
option. TOIA [23] is a complete assessment creation and delivery system, and is significant because it uses QTI
as its native format. TOIA, which is free to use within the UK educational system, was written as a closed interface
system but development is taking place to expose it as a set of web services [24].
3. ELEMENTS OF CAA
Ease of question authoring is a significant proportion of the work in being able to deliver CAA. By authoring, we
mean both the assembling of an individual question, possible responses and allocated marks to form an item and
the aggregation of these items into the assessment to be delivered to a student. Authors of objective tests must
not only ensure the soundness of their tests they must also get the assessment into the assessment system. It is
clearly in the best interests of assessment software to make this process as painless as possible. However, it may
be found that once inside the assessment system even standard QTI question items may not be exported
unaltered to other systems. One cause of this is ambiguities in the QTI version one specification; with version two
much care has been taken to minimise this problem. At the current time, there are no QTI version two authoring
tools available for evaluation; this is unsurprising, as the specification was not finalised until January this year.
Stand-alone tools for authoring QTI question items include Canvas Learning Author [4] and xDLSofts QTI Ready
Designer [26]. Received wisdom suggests that by using one of these tools to author assessments before
uploading to the delivery system vendor lock-in may be avoided. Because of the richness of QTI, authoring tools
can become overly complicated by giving users more options than they are likely to need. An associated problem
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is encountered when the authoring tool does not allow the richness of logic required by the user, in this situation
they may need to modify the XML source by hand. These problems could be reduced by providing users with a
choice of authoring services, possibly dynamically switching between them as needed.
To illustrate the potential complexity of authoring objective tests, listed below are most of the question types that
QTI can describe; these can be combined with the ability to deliver hints, reduced marks and template based
questions with random dynamically generated numeric values. QTI can be highly expressive.
multiple choice - Choose the one correct response.
multiple response - Choose all the correct responses.
true/false, yes/no - A simple binary choice.
image hot spot - Identify the required area(s) on an image (by clicking).
fill in the blank - Insert the missing words
text short answer - Free form text field.
essay text - Long response text field, likely to require human marking.
numeric entry - Enter the correct number.
slider - Move slide bar pointer to correct value.
drag and drop - Place objects into the correct locations.
order objects - Rank objects according to the given criteria.
match item - Connect the objects in pairs.
connect the points - Create an ordered connection of a set of points.
Macromedia Flash Object - QTI player runs the Flash program it is given. The QTI player has a very limited interface to the
Flash program, though there is no limit on the complexity of the logic that can be expressed inside the Flash object.
4. ASSESSMENT LIFECYCLE
Storage of assessment and question items is commonly referred to as item banking. The IBIS report [20]
describes in detail the functionality required of an item bank; it was informed by the study of a number of existing
item banks including e3an [7] and Scottish Colleges Open Learning Exchange Group’s COLA project. COLA is
now a highly successful live system providing assessments across the curriculum to Further Education colleges
across Scotland, where they are presented inside several different VLEs. Interestingly both e3an and COLA
acquired their content by asking authors to fill out MS Word templates to describe their questions; these were then
parsed automatically for storage.
The requirements of an item bank include facilities to store, search for and retrieve individual items. Extended
functions include the ability to assemble items into assessments and to be able to deliver alternative but equivalent
items. The IBIS report recognizes the need to ensure that the items in the bank have been properly peer reviewed
as part of a quality assurance process; it also recommends that the usage data concerning an item be fed back
into the system. With feedback on usage the effectiveness of individual question items and possible bias can be
monitored, this may result in items being removed from further use. As with any data repository use of item banks
arouses questions concerning user identity, security and availability.
Sclater and Howie [21] describe the ultimate online assessment engine; the paper describes 21 user roles in an
assessment system and gives detailed use cases and user requirements of the system. In 2001 they evaluated
two commercial products against their requirements and found nearly all of their requirements satisfied. From the
technical perspective most of the challenges involved in delivering CAA have been met. Candidates can be
authenticated and remote presentation, response gathering and feedback can be delivered using web browsers.
Delivery of CAA is now a fairly well understood area but is often not completely integrated into students’ other
educational experiences. Augmenting the assessment delivery system with open interfaces would allow much
finer granularity of control in integrating this with the rest of the virtual learning environment.
As well as showing the user roles Figure 1 illustrates the sets of data that must be coordinated to ensure that the
assessment runs correctly, and demonstrates the point that there is much more to the assessment task than the
assessment delivery engine alone.
There are a number of tasks that must be carried out before an assessment can be delivered, including authoring
of questions, quality control of questions, selection of suitable questions to create a test, and selection of delivery
conditions, such as the group to take the assessment, on what platform and when? Once a student has finished
an assessment there are still a number of tasks that the system has to perform relating to the student and to the
assessment as a whole. Marks may need to be stored permanently in a grade book, feedback may need to be
given to the student, and the results may need some form of moderation. As described already feedback from
assessments can also be fed back into the item bank they were obtained from to augment quality assurance
procedures. Analysis of assessment marks across a class may be used both to analyse the effectiveness of the
assessment and to identify problem areas for the entire class with the subject material. Analysis of individual’s
marks across a number of assessments can identify anomalies that may indicate students with specific difficulties
and also situations where some form of cheating may have occurred.
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The work on defining the Ultimate Assessment Engine is now forming the basis of ongoing work within the ELearning
Framework [25] (described in the next section), to build a reference model for assessment services.
Figure 1: The Ultimate Assessment Engine (as described by Sclater and Howie 2003
5. REASONS FOR USING SERVICES
A SOA is becoming recognized as a highly flexible way of building a large application from components [2],[3].
From an institutional point of view this enables collaboration between universities, faster deployment of new
functionality, and support for pedagogic diversity, and avoids lock in to single vendor solutions with the possible
attendant costs.
From a technical point of view the open interfaces of the components make it relatively simple to connect
components in novel and custom ways, encourage interoperability, and facilitate replacing one service with another
to provide the same functionality in different ways. Here we describe three different learning environment projects
and comment on their methodology.
The E-Learning Framework (ELF) [25] is an initiative by the U.K's Joint Information Systems Committee (JISC),
Australia's Department of Education, Science and Training (DEST), and the Carnegie Mellon Learning Services
Architecture Lab (LSAL). The ELF does not set out to build a learning management system but a framework
which is a road map of functions that could be used in planning institutional e-learning systems. So far over 40
separate component functions have been identified which might be needed inside a comprehensive MLE. This
approach allows production of architectures based on standards which enable interoperability, providing a common
understanding for future developments. It also allows the community to more easily identify gaps or major barriers
to progress on which to focus funding for development activity
Discrete packages of funding have been allocated to investigate the requirements of individual components and
also to build exemplar services to satisfy these requirements. By steering the project in this way it is hoped that a
critical mass will be achieved where institutions can spontaneously develop component services to augment an
existing working system.
The service oriented approach was adopted in the ELF because it separates out the contract between the
providers and consumers from the application itself. This approach is also neutral in terms of platform and
language. The upshot of both of these things is that ELF can fit with commercial systems such as Blackboard and
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Web CT, and open source systems such as Moodle, regardless of the technology they're built on. The challenge
now for ELF is the design of the "fabric" services of workflow, security, and management. The question is whether
to build services that are "fat" and complex or "thin" and simple.
The work on ELF has a large overlap with the Grid based work of the e-Science community, particularly in the area
of Virtual Research Environments. At a recent ELF Conference the two communities produced a useful report [14]
on the requirements overlap.
The Sakai Project [19] is being run by a consortium of universities, in the USA, to create an open source,
extensible VLE. When asked to explain some of the benefits of the modular architecture of Sakai against a
commercial VLE, Sakai Project Chief Architect, Chuck Severance said: [12]
“What we do at universities is teaching, learning and research. We can't outsource the software that supports that- you
can't outsource your destiny. You shouldn't have to negotiate with an outside commercial provider about things that directly
affect your core business. So, building your own MLE software allows an organization to take charge of its own destiny.
But building a completely unique package for your own use is really a bit lonely and somewhat expensive. By working
together in Sakai, we can control our own destinies and avoid the cost and risk involved in the solo path. Major research
institutions can build the large components and the framework, smaller ones can customize the tools they need.”
Whilst Sakai is not currently using a service based paradigm, its designers are aware of the value of service
architecture and recognize that Sakai may have service interfaces inserted in the future. The pressure to deliver a
complete running system led to the decision to use more mature technology based on Open Knowledge Initiative’s
Open Service Interface Definitions and extended Application Programming Interfaces..
The Department of Education Tasmania provides education for the 70,000 pupils in schools and colleges across
Tasmania, Australia. They have undertaken a pioneering case study, LeAP [13], examining the building of a SOA
Managed Learning Environment. LeAP was started in 2002 and was the first large project of its kind. The
department describes itself as an early adopter of technology. They installed WebCT in 1999, but are clearly
concerned about the implications of being locked into a proprietary system. The reports commissioned to start the
ELF were written in collaboration with some of the key figures in LeAP.
6. CURRENT WORK
Here we describe a number of state of the art bodies of work which all have a significant contribution to make
towards a SOA for CAA.
The European Learning Grid Infrastructure (ELeGI) describes one of its goals as to define and implement an
advanced service-oriented Grid based software architecture for learning In existing SOAs based on protocols such
as web services, the issues of security, identity, access management and managing transaction persistence are
not managed at the protocol level. Having to address these issues whenever a new service is created is a
cumbersome overhead. By deploying its services over grid middleware ELeGI will remove much of the burden on
individual service developers in addressing these problems. Grid middleware will be a valuable tool for the VLE
service author.
Remote Query Protocol (RQP) [22] is being developed by a JISC funded project, Serving Maths, to create a
protocol to support remote rendering and processing of question items in an SOA. This is a problem that has been
a source of constant concern to those assessing the mathematically founded disciplines; very few available
engines have the required sophistication to render mathematics. RQP is aware of the fragility of a distributed
architecture and includes mechanisms for fail-over and load balancing by the project. Demonstration systems
using RQP to deliver mathematics questions have been able to use a choice of question renderers for an
assessment depending on the demands of the question. This is an excellent example of how the SOA puts power
in the hands of the assessment authors.
ASSIS [1] is funded by JISC and is currently one of the partners being used to test RQP. The aim of ASSIS is to
connect up an item bank with a QTI player and a service for running IMS Simple Sequencing [10] (a method of
dynamically changing a user’s path through learning material). QTIRun, the QTI player service used by ASSIS, is
an extension of APIS the first publicly available system to play questions written in the latest QTI specification,
version two. Item banking services will be provided both by an open interface to TOIA and also by an interface to
Samigo, the Sakai Project assessment system. ASSIS is using CAA to give formative feedback to students as
they work their way through learning packages. These packages are augmented with Simple Sequencing rules
that allow authors to script a student’s path through the learning material and adapt to different students’
educational needs. By combining different and also equivalent services ASSIS is providing a small-scale fully
functional test-bed of a SOA.
JORUM+ [11] provides a repository of educational content for UK further and higher education. The main functions
of JORUM are to offer institutions a secure, resilient location in which to store their educational content and also to
facilitate sharing of content between institutions without the need for them to negotiate through each others
network security policies. JORUM is currently in an extended testing phase and is being used by a number of early
adopters. Importantly JORUM is addressing the legal considerations, including intellectual property rights,
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connected to the content it holds. Resources can be submitted to JORUM in a variety of formats including
references to material held outside JORUM. To facilitate searching, resources are tagged with Learning Object
Metadata. When searching for material users can search by keyword and also by using a graphical classification
structure. To enable end users to select appropriate resources for use in their institution, all resources within
JORUM can be previewed. The lessons learnt by JORUM will be useful to any future question item banking
service.
D+ [5] is a service for conducting federated searches; it allows users to search for information hidden from simple
searching mechanisms. D+ provides a service for searching the deep web hidden under database style indexing
systems and other dynamic content generators. By being aware of a number of search protocols such as the
Z39.50 protocol for searching libraries, D+ can present users with search results compiled from a number of
sources. Federated search is important in the context of SOA CAA as it could be used to combine searches over a
number of item banks that provide differing interfaces to their content.
Security in eLearning, and particularly assessment, is an important issue from a number of points of view, often
summed up as “the three As”; authentication, authorization and administration. We must know that the student
taking an assessment is authorized to take this test and has been authenticated as the person they claim to be,
and when they have completed the test we must understand how to route the results. These functions are currently
causing enormous problems within the world of global campuses working with heterogeneous software systems,
and it is the promise of robust proven grid middleware that is one of the major attractions of this work.
7. COOKING UP AN ASSESSMENT SYSTEM
While developing all the services described, it is important not to forget that on their own they do not deliver an
assessment system. To encourage uptake of the services discussed it will be necessary to develop exemplar or
proof of concept consumers that demonstrate how the services may be integrated. Once these are in place then
the research community will be able to experiment with innovative ways of using the services from inside a VLE. It
is envisaged that the ability to modify the environment easily and leverage one service to develop another, will
encourage the development of compound service aggregation. This then exposes a whole new issue of how to
manage performance in the face of large quantities of service calls to services whose implementation is hidden.
The ability to plug in modular services will also simplify comparison of the effectiveness of parallel services that
provide subtly different environments.
We look forward to the day when the services for CAA are sufficiently sophisticated that a learner, working on their
own, would be able to select appropriate questions to help them assess their own progress in their learning, and to
get sensible feedback and help. This would be truly personalized assessment.
8. ACKNOWLEDGEMENTS
This work has been supported by the European Commission FP6-IST IP 002205 “European Learning GRID
Infrastructure” (ELeGI), and also by JISC Exchange for Learning Strand B Project, “Technologies for Online
Interoperable Assessment” (TOIA).
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