CrowdLearn: Crowd-sourcing the Creation of Highly-structuredE-Learning Content

Darya Tarasowa, Ali Khalili, Soren Auer, Jorg UnbehauenAKSW Research Group, Institute of Computer Science

University of Leipzig, Postfach 100920, 04009 Leipzig, Germany{lastname}@informatik.uni-leipzig.de

http://aksw.org

Keywords: e-learning, LMS, crowdsourcing, (semi-)structured learning objects, SCORM

Abstract: While nowadays there is a plethora of Learning Content Management Systems, the collaborative, community-based creation of rich e-learning content is still not sufficiently well supported. Few attempts have been madeto apply crowd-sourcing and wiki-approaches for the creation of e-learning content. However, the paradigm isonly applied to unstructured, textual content and cannot be used in SCORM-compliant systems. To address thisissue we developed the CrowdLearn concept to exploit the wisdom, creativity and productivity of the crowdfor the creation of rich, deep-semantically structured e-learning content. The CrowdLearn concept combinesthe wiki style for collaborative content authoring with SCORM requirements for re-usability. Therefore, itenables splitting the learning material into Learning Objects (LOs) with an adjustable level of granularity. Inorder to realize the CrowdLearn concept, a novel data model called WikiApp is devised. The WikiApp datamodel is a refinement of the traditional entity-relationship data model with further emphasis on collaborativesocial activities and structured content authoring. We implement and evaluate the CrowdLearn approachwith SlideWiki – an educational platform dealing with presentations and assessment tests. The article alsocomprises results of a usability evaluation with real students.

1 Introduction

While nowadays there is a plethora of LearningContent Management Systems (LCMS), the collab-orative, community-based creation of rich e-learningcontent is still not sufficiently well supported. Fewattempts have been made to apply crowd-sourcingand wiki-approaches for the creation of e-learningcontent. Wikiversity1, for example, is a WikimediaFoundation project aiming to leverage standard wikitechnology for the creation of hypertext e-learningcontent. Peer 2 Peer University (P2PU)2 and Plan-etMath3 are other examples which employ crowd-sourcing to create rich e-learning content. P2PU helpsusers to navigate the wealth of open education materi-als and supports the design and facilitation of courses.The PlanetMath is a project to aiming to become acentral repository for mathematical knowledge on theweb, with a pedagogical mission. However, we deem,that no real attempt has been made so far to truly ap-ply the concepts behind wikis and crowd-sourcing to

1http://wikiversity.org/2http://p2pu.org/3http://planetmath.org/

develop a specifically tailored technology supportingthe creation of highly-structured, SCORM-compliante-learning content.

Sharable Content Object Reference Model(SCORM) (sco, 2011a) as one of the community-approved standards, requires the transformation ofthe learning material into the sequence of annotatedSharable Content Objects (SCOs). The granularityand sequencing of the SCOs should be determined bythe content author depending on the audience needsand preferences (sco, 2011b). Ward Cunningham’swiki (Leuf and Cunningham, 2001) paradigm ismainly only applied to unstructured, textual content.This limitation makes it difficult or even impos-sible to use the wiki style of content authoring inthe SCORM-compliant learning platforms. As aresult, a proper community collaboration, authoring,versioning, branching, reuse and re-purposing of(semi-)structured educational content similarly as weknow it from the open-source software communityis currently not supported. To address the issue wedevelop the CrowdLearn concept.

CrowdLearn exploits the wisdom, creativity andproductivity of the crowd for the creation of rich,

deep-semantically structured e-learning content. Itcombines the wiki style of collaborative content au-thoring with SCORM requirements for re-usability.Therefore, it enables splitting the learning materialinto Learning Objects (LOs) with an adjustable levelof granularity. The CrowdLearn concept is based onfive fundamental components (cf. Section 3): stan-dard compliance, semantic structuring, enhanced pos-sibilities for reuse and re-purpose, crowd-sourcingand social networking.

In order to implement and evaluate theCrowdLearn concept, we created a showcaseapplication named SlideWiki. SlideWiki deals withthe collaborative creation of original e-learningcontent such as presentations, slides, diagrams andself-assessment tests. During the implementationof the CrowdLearn concept, we faced several chal-lenges (cf. Section 4). For enabling the high-levelcollaboration, all content should be versioned, similarto the wiki paradigm. SCORM has direct supportfor multiple-version content objects. However,we needed rules for triggering the creation of newrevisions. Our findings on this issue are presentedin Section 4.2. The next challenge was the SCORMrequirement for the content to be structured. To solvethis we developed the WikiApp data model (see Sec-tion 4.1) that organizes the relations between differentcontent objects. Finally, the third challenge was toinvolve the learners in the process of content creation.We addressed this issue by providing support forsocial networking activities. Both content owners andstudents are able to participate in discussions aboutthe learning material. While SCORM allows contentengineers to do the sequencing, we allow it to be doneby learners as well. As a consequence, semanticallystructured learning objects can be created and editedin a truly collaborative way. We further evaluated theCrowdLearn concept by conducting a comprehensiveusability study with real students using SlideWiki (cf.Section 5).

2 Related work

Related work can be roughly divided into the fol-lowing two categories:

Collaborative creation of e-learning content. Theimportance of creating reusable and re-purposable e-learning objects is widely accepted by the e-learningcommunity (Devedzic, 2006). However, most ofthe works address the learning object reuse problemrather by means of semantic meta-data annotations,content tagging and packaging than by creating richly

structured, reusable learning objects from the ground.The importance of creating learning objects alreadywith reuse in mind was, for example, stated by (Pe-dreira et al., 2009): Content ... should be repre-sented not as an object of study but rather as neces-sary elements towards a series of objectives that willbe discovered in the course of various tests. Thereare only few approaches for the direct authoring ofreusable content, such as, for example, learning ex-amples creation (Kuo et al., 2008) or semantic struc-turing and annotation of video fragments (Barriocanalet al., 2011).

We should also mention the Learning ObjectsRepositories (LORs), that allow to produce struc-tured reusable content. The first of them, Connex-ions (http://cnx.org/), presents the learning materialas a combination of paragraphs, each of them couldbe easily edited or deleted. However, this structur-ing is done more for comfortable editing and does nothave any functional benefits: the paragraphs cannotbe reused or annotated independently. Thus, Con-nexions presents just an improved user interface forwiki-based system. The second example of structur-ing, that is more close to our idea, is LeMill4. LeMillprovides a way of collaborative editing of the presen-tations by implementing presentations as a group ofimages which can be edited collaboratively. However,to edit a slide, a user has to replace it with anotherone. Also, it is impossible to have several subgroupsof the slides within a presentation. The search throughthe slides (not presentations) is also not implemented.Thus, slides cannot be manipulated as independentlearning objects.

The CrowdLearn concept differs from the exist-ing approaches for managing e-learning content. Itenables the construction of semantically structuredlearning objects from existing sources by combining,reordering and simple editing. By the term seman-tically structured object we mean that all the partswithin the structure own all the attributes and methodsof the object type, or, in the case of learning content,are complete and fully-functional LOs.

Wiki-based collaborative knowledge engineering.The importance of wikis for collaborative knowledgeengineering is widely acknowledged. In (Richards,2009), for example, a knowledge engineering ap-proach which offers wiki-style collaboration, is intro-duced aiming to facilitate the capture of knowledge-in-action which spans both explicit and tacit knowl-edge types. The approach extends a combinedrule and case-based knowledge acquisition technique

4http://lemill.net/

Figure 1: CrowdLearn concept.

known as Multiple Classification Ripple Down Rulesto allow multiple users to collaboratively view, defineand refine a knowledge base over time and space. In amore applied context, (Haake et al., 2005) introducesthe concept of wiki templates that allow end-users todefine the structure and appearance of a wiki pagein order to facilitate the authoring of structured wikipages. Similarly the hybrid wiki approach (Mattheset al., 2011) aims to solve the problem of using (semi-)structured data in wikis by means of page attributes.In our approach we apply the wiki paradigm to thecreation and collaboration around (semi-)structuredlearning objects.

3 CrowdLearn Concept

We see the CrowdLearn concept as an applicationof crowd-sourcing techniques to the e-learning con-tent creation, re-purpose and reuse. As shown in Fig-ure 1, the concept is based on the following five strate-gies:

Standard-compliance The costs associated withbuilding high-quality e-learning content are high.One solution to decrease the costs is to author struc-tured and reusable e-learning content that can berepurposed in different ways. To facilitate this, itshould be possible to migrate content between dif-ferent Learning Management Systems (LMSs). How-ever, often content migration is not completely ad-equate and can thus result in loss of valuable con-tent, meta-data or structure. Even if the transfer ispossible, moving the content between systems canbe more costly than just redeveloping that course inthe new system. The strategy to overcome this chal-lenge is the standard-compliance of both LMS and

content. In that regard, we adopted the SCORMstandard (sco, 2011a) and practical recommenda-tions (sco, 2011b) and expanded the standard for thecollaborative model.

Semantic structuring Instead of dealing with largelearning objects (often whole presentations or tests),we decompose them into fine-grained learning arti-facts. Thus, rather than a large presentation, user willbe able to edit, discuss and reuse individual slides; in-stead of a whole test she/he will be able to work on thelevel of individual questions. This concept efficientlyfacilitates the reuse and re-purpose of the learning ob-jects. To implement the concept, we employ the Wiki-App approach, as discussed in Section 4.1.

Reuse and re-purpose The benefits of reuse andrepurposing are: (1) increasing the cost efficiencyof content creation, (2) increasing the quality of e-learning content and (3) supporting the evolution andadaptation to new requirements. To increase theeconomic efficiency of e-learning, content should bereused for a long period of time. Then, the devel-opment costs can be amortized over several years.However, the student expectations for higher qualitye-learning experience increase, and new technologyemerges so quickly that most courses need redevelop-ing every 3-4 year (Jones, 2002). Instead of the fullredevelopment, the content can slightly evolve. In thatcase the courses remain competitive with regard to theprovisioning of high quality e-learning content. Thepossibility to reuse and re-purpose is crucial for the e-learning content evolution. Also, re-purposing allowsto increase the efficiency by teaching more learnerswith the same content.

Crowd-sourcing There are already vast amountsof amateur and expert users which are collaboratingand contributing on the Social Web. Harnessing thepower of such crowds can significantly enhance andwiden the distribution of e-learning content. Crowd-sourcing as a distributed problem-solving and pro-duction model is defined to address this aspect ofcollective intelligence (Howe, 2006). CrowdLearnas its main innovation combines the crowd-sourcingtechniques with the creation of highly-structured e-learning content. E-learning material when com-bined with crowd-sourcing and collaborative socialapproaches can help to cultivate innovation by col-lecting and expressing (contradicting) individual’sideas. As Paulo Freire wrote in his 1968 book Ped-agogy of the Oppressed, ‘Education must begin withthe solution of the teacher-student contradiction, byreconciling the poles of the contradiction so that both

are simultaneously teachers and students...’. There-fore, crowd-sourcing in the domain of educationalmaterial not only increases the amount of e-learningcontent but also improves the quality of the content.

Social networking The theoretical foundations fore-Learning 2.0 are drawn from social construc-tivism (Wang et al., 2012). It is assumed that stu-dents learn as they work together to understand theirexperiences and create meaning. In this view, teach-ers are knowers who craft a curriculum to support aself-directed, collaborative search and discussion formeanings. Supporting social networking activitiesin CrowdLearn enables students to proactively inter-act with each other to acquire knowledge. With theCrowdLearn concept we address the following socialnetworking activities:• Users can follow individual learning objects as

well as other users activities to receive notifica-tion messages about their updates.

• Users can discuss the content of learning objectsin a forum-like manner.

• Users can share the learning objects withintheir social network websites such as Facebook,Google Plus, LinkedIn, etc.

• Users can rate the available questions in terms oftheir difficulty.Besides increasing of the learning process qual-

ity, social activities improve the quality of the cre-ated learning material. Even when answering a quiz,users can contribute by analysing the quality of thequestions and making suggestions of how to improvethem. Thus, the knowledge is being created not onlyexplicitly by contributors, but also implicitly throughdiscussions, answering the questions of assessmenttests, or in other words through native learning activ-ities.

4 CrowdLearn Implementation

We implement and evaluate the CrowdLearn con-cept with SlideWiki 5 – a web-based crowd-learningplatform. SlideWiki deals with two types of (semi-)structured learning objects: slide presentations andassessment tests. SlideWiki follows our proposedWikiApp data model to facilitate the creation, re-purpose and reuse of learning objects. In this sec-tion we first elaborate on the WikiApp data model andthen discuss the technical implementation details ofthe SlideWiki application.

5http://slidewiki.aksw.org

4.1 WikiApp Data Model

The WikiApp data model is a refinement of the tra-ditional entity-relationship data model. It adds someadditional formalisms in order to make users as wellas ownership, part-of and based-on relationships first-class citizens of the data model. A set of content ob-jects connected by part-of relations can be arrangedand manipulated in exactly the same manner, as anindividual non-structured object. The model nativelysupports versioning and structuring of the differentcontent objects.

The WikiApp data model comes with a DomainSpecific Language (DSL)6 which allows the model-driven generation of CrowdLearn applications. Weillustrate the WikiApp model in Figure 2 and formallydefine it as follows:

Definition 1 (WikiApp data model). The WikiAppdata model WA can be formally described by a tripleM = (U,T,O) with:

• U - a set of users.• T - a set of content types with associated property

types Pt having this content type as their domain.• O = {Ot∈T} with Ot being sets of content objects

for each content type t ∈ T .

Each Ot consists of content objects ot,i with i ∈ ITbeing a suitable identifier set for the content ob-jects in Ot . Each ot,i comprises a set of propertiesPt,i = Attrt,i ∪ Relt,i. Attrt,i is a set of literal, pos-sibly typed attributes, and Relt,i is a set of relation-ships with other content objects; The only necessaryattribute for all content objects is ct,i, which con-tains the creation timestamp of the object ot,i. Relt,ican particularly include the following designated re-lationships to related objects:

• partt,i ⊂O refers to set of the content objects con-tained in ot,i ;

• baset,i ∈ Ot refers to base content object fromwhich the object ot,i was derived;

• usert,i ∈U refers to a user being the owner of theot,i;

The WikiApp model assumes that all content ob-jects are versioned using the timestamp ct,i and thebase content object relation bt,i. In the spirit of thewiki paradigm, there is no deletion or updating ofexisting, versioned content objects. Instead new re-visions of the content objects are created and linkedto their base objects via the base-content-object rela-tion. All operations have to be performed by a specificuser and the newly created content objects will have

6More information available at: http://slidewiki.aksw.org/wikifier

Figure 2: Conceptual view of the WikiApp data model.

this user being associated as their owner. In practice,however, usually only a subset of the content objectsare required to be versioned. For auxiliary content(such as user profiles, preferences etc.) it is usuallysufficient to omit a base content object relation. Forreasons of simplicity of the presentation and space re-strictions we have omitted a separate consideration ofsuch content here. However, this is in fact just a spe-cial case of our general model, where the base contentobject relation baset,i is empty for a subset of the con-tent objects.

The model is compatible with both the relationaldata model and the Resource Description Framework(RDF) data model (i.e. it is straightforward to mapit to each one of these). When implemented as a re-lational data, content types correspond to tables andcontent objects to rows in these tables. Functionalattributes and relationships as well as the owner andbase-content-object relationships can be modeled ascolumns (the latter three representing foreign-key re-lationships) in these tables. The implementation ofthe WikiApp model in RDF is slightly more straight-forward: content types resemble classes and con-tent objects instances of these classes. Attributesand relationships can be attached to the classes viardfs:domain and rdfs:range definitions and di-rectly used as properties of the respective instances.For reasons of scalability we expect the WikiApp datamodel to be mainly used with relational backends.However, we also added a Linked Data interface us-ing Triplify (Auer et al., 2009) (cf. Section 4.2).

Watching the users, as well as following the learn-ing objects operations are natively supported by themodel. This allows users to receive the informationabout changes of the followed content object or newobjects created by the watched user. Also, these oper-ations allow to easily find the followed object or user.

Our SlideWiki example application uses two im-plementations of WikiApp data model. The first im-

plementation is used for managing slides and pre-sentations. It includes individual slides (consistingmainly of HTML snippets, SVG images and meta-data), decks (being ordered sequences of slides andsub-decks), themes (which are associated as defaultstyles with decks and users) and media assets (whichare used within slides). The second implementationwas developed for managing questions and assess-ment tests. It includes questions for the slide material(the question is assigned to all slide revisions), tests(which could be organized manually by user or cre-ated automatically in accordance with the deck con-tent), and answers (which are the part of the ques-tions).

We implicitly connected these two WikiApp in-stances by adding two relations. Firstly, we assignedquestions to slides. Thus, during the learning processusers are able to answer the tests and have a look atthe assigned slide if necessary. The important issuehere is that we assign question not to individual sliderevision, but for the slide itself. This decision givesan opportunity to create a new slide revision, that al-ready has a list of questions, collected from other re-visions. Secondly, we assigned assessment tests toconcrete deck revisions. Thus the automatically cre-ated test saves the structure of the corresponding deckrevision. This allows us to use module-based assess-ment to score the test results.

4.2 SlideWiki Implementation

The SlideWiki application makes extensive use ofthe model-view-controller (MVC) architecture pat-tern. The MVC architecture enables the decouplingof the user interface, program logic and database con-trollers and thus allows developers to maintain eachof these components separately. The implementationcomprises the main components: authoring, changemanagement, import/export, linked data interface, e-

Figure 3: SlideWiki conceptual scheme.

assessment and translation. We briefly walk-throughthese components in the sequel.

Authoring. SlideWiki employs an inline HTML5based WYSIWYG (What-You-See-Is-What-You-Get) text editor for authoring the presentation slides(cf. Figure 5, image 1). Using this approach, userswill see the slideshow output at the same time as theyare authoring their slides. The editor is implementedbased on ALOHA editor7 extended with someadditional features such as image manager, sourcemanager, equation editor. The inline editor uses SVGimages for drawing shapes on slide canvas. EditingSVG images is supported by SVG-edit8 with somepredefined shapes which are commonly used in pre-sentations. For logical structuring of presentations,SlideWiki utilizes a tree structure in which users canappend new or existing slides/decks and drag & dropitems for positioning. When creating presentationdecks, users can assign appropriate tags as well asfooter text, default theme/transition, abstract andadditional meta-data to the deck.

Change management. Revision control is nativelysupported by WikiApp data model. We just definerules and restrictions to increase the performance.There are different circumstances in SlideWiki forwhich new slide or deck revisions have to be created.For decks, however, the situation is slightly morecomplicated, since we wanted to avoid an uncon-trolled proliferation of deck revisions. This would,however, happen due to the fact, that every change

7http://aloha-editor.org/8http://code.google.com/p/svg-edit/

user requests to copy a deck

add/remove item to/from deck

change the order of items in a deck

replace/change the content of a deck

change the slide content

new slide revision

user is the owner ofthe container deck

yesno

yes

no

new deck revision

container deck hasusage somewhere else

Figure 4: Decision flow during the creation of new slide anddeck revisions.

of a slide would also trigger the creation of a newdeck revision for all the decks the slide is a part of.Hence, we follow a more retentive strategy. We iden-tified three situations which have to cause the creationof new revisions:

• The user specifically requests to create a new deckrevision.

• The content of a deck is modified (e.g. slide or-der is changed, change in slides content, adding ordeleting slides to/from the deck, replacing a deckcontent with new content, etc.) by a user which isneither the owner of a deck nor a member of thedeck’s editor group.

• The content of a deck is modified by the owner ofa deck but the deck is used somewhere else.

The decision flow is presented in Figure 4. In addi-tion, when creating a new deck revision, we alwaysneed to recursively spread the change into the parentdecks and create new revisions for them if necessary.

Import/Export. SlideWiki implementation ad-dresses interoperability as its first class citizen. Asshown in Figure 3, SlideWiki supports import/exportof the content from/to existing desktop applicationsand LORs thereby allowing users from other LMSsto access the created content. The main data formatused in SlideWiki is HTML. However, there are otherpopular presentation formats commonly used bydesktop application users, such as PowerPoint .pptxpresentations, LaTeX and others. We implementedimport of the slides from .pptx format and work onthe LaTeX format support is in progress.

Linked Data Interface. While sharing and reusingeducational data across institutional and nationalboundaries is a general goal for both the public andthe private education sector, the last decade has seen

Figure 5: Four screenshots of SlideWiki features. 1 - Tree structure of the presentation, inline WYSIWYG editor; 2 - Editingof a question and manual assigning to a test using lists; 3 - Question in learning mode with correct answers displayed; 4 -Module-based scoring of an assessment test.

a large amount of research dedicated to Web-scale in-teroperability. For example, LinkedEducation.orgis an open platform which promotes the use of LinkedData for educational purposes. In order to enablethe export of SlideWiki content on Data Web asLORs, we employed the RDB2RDF mapping toolTriplify (Auer et al., 2009) to map SlideWiki con-tent to RDF and publish the resulting data on the DataWeb. The Triplify configuration for SlideWiki wascreated manually according to IEEE LOM standardand can be changed to support specific LORs. TheSlideWiki Triplify Linked Data interface is availablevia: http://slidewiki.aksw.org/triplify.

E-Assessment. SlideWiki supports the creation ofquestions and self-assessment tests based on slide ma-terial. Each question has to be assigned to at leastone slide. Important note here, that the question isassigned not to the slide revision, but to slide itself.Thus, when a new slide revision appears, it continues

to include all the list of previously assigned questions.Questions can be combined into tests. The automati-cally created tests include the last question revisionsfrom all the slides within the current deck revision.Manually created tests present a collection of chosenquestions and currently cannot be manipulated as ob-jects (cf. Figure 5, image 2). Thus, in our implemen-tation only questions and answers have to be placedunder the version control. However, their structure istrivial and the logic of creating their new revisions isintuitive. We just restricted the number of new revi-sions to be created similarly with the decks: changesmade by the question owner do not trigger a new re-vision creation.

For now, only multiple-choice (and multiple-mark) question type is implemented, however in thefuture we plan to expand the list of supported types.To score the results the student (or the teacher) canchoose one of five implemented algorithms. Thus, di-chotomous scoring gives points only when the answerwas fully correct, other algorithms also count par-

tially answered questions. Within other algorithms weimplemented our balanced approach for scoring themultiple-mark questions, described in details in (?).All five algorithms use the dynamically accumulateddifficulty d of the question as the number of points forthe fully correct response:

d =incorr

all(1)

If the user prefers to use dichotomous scoring, thevalues of incorr and all mean, respectively, the accu-mulated number of incorrect answers and all answersof that question by any of users. In a case of partialscoring, incorr is determined as follows:

incorr =n

∑i=1

(1− pi

di), (2)

where n - number of attempts for the question, di -difficulty (or maximal points), that the question hadat the moment, when the ith attempt was made, pi -points obtained in the ith attempt

After the difficulty is determined, it’s scaled to(1,dmax], where dmax is the maximal weight, that aquestion can have. dmax is set up by the system ad-ministrator only for the users’ comfort. In SlideWikiwe set it up to 5.

Students can start a chosen test (manually cre-ated or automatically collected) in one of two pos-sible modes: “learning” or “examination”. In learn-ing mode student can ask to show the slide, to whichthe question is assigned to remind the material, orsimply show the correct answers (cf. Figure 5, im-age 3). Thus, student should not spend time to findthe material. However, after the user asked to showher/him either the slide or correct answers she/he willnot get any points for the question. In examinationmode these features are disabled.

After choosing the mode the user can also set upthe amount of questions (all, all the difficult or con-crete amount) and the order to show them (randomor increase the difficulty). As the amount of questionscan differ for the same test, we show the test results asa percentage of the maximum points for exactly thisselection of question.

Our architecture allowed us to implement module-based scoring. Each module of the assessment testpresents a sub-deck of the presentation and is scoredindividually. Then, all the “parent” modules arescored as a sum of “children” points and finally thewhole test is scored as a sum of all the points for allthe modules (cf. Figure 5, image 4).

Translation Our architecture allowed us to imple-ment a translation feature backed by the Google

Translate service. After the translation into one of 54supported languages, the presentation can be editedindependently from the original one. However, westore the information about the original version andnow we are working on the possibility to partially up-date the translated presentation when the original onewas changed. Without such a possibility we facedwith an important challenge. As we allow the ownerof the revision to change it without creation of a newrevision, it was an important issue: either we shouldallow the multiple translation of the same revisioninto the same language or not. For now we decidedto allow it, however, this led us to the situation, thatwe would get several identical presentations with thecontent of bad quality, as it was translated automat-ically and was not edited manually. However, wecould not disable the multiple translations, as in thatcase it would be for example impossible to get thetranslations of new slides, if they were added by theowner. Thus, the connection between original andtranslated presentations seems to be crucial. Alsowe think about supporting of the user and communitythesauri.

5 Evaluation

To evaluate the real-life usability of SlideWiki,we used it for accompanying an information systemslecture at Chemnitz Technical University. We struc-tured the slides within the lecture series and addedquestions for student self-assessment before the fi-nal exam. We informed them about the different e-learning features of SlideWiki, in particular, how toprepare for the exam using SlideWiki. The exper-iment was not obligatory but students actively con-tributed by creating additional questions and fixingmistakes. The experiment was announced to 30 stu-dents of the second year and 28 of them registered atSlideWiki.

The students were working with SlideWiki forseveral weeks, and we collected the statistics for thatperiod. During that period, they created 252 newslide revisions which some of them were totally newslides, others were improved versions of the originallecture slides. Originally the whole course had 130questions, and students changed 13 of them, fixingthe typos or adding additional distractors to multiplechoice questions. In total, students performed 287self-assessment tests. The majority of these used theautomatically and randomly created tests covering thewhole course material. 20 tests included only difficultquestions, 2 asked to show the questions with increas-ing difficulty. This showed us that the students liked

Figure 6: Results of SlideWiki evaluation survey: mean µ and standard deviation σ.

the diversity of test organization. Students also likedthe possibility to limit the number of questions – 80attempts were made with such a setting. 8 studentsreached the 100% result for the whole course. On av-erage, it took them 6 attempts before they succeeded.

After the experiment we can claim, that more ac-tive SlideWiki users received better marks on the realexamination. It shows that SlideWiki not only allowsstudents to prepare for the examinations, but also en-gages them in active participation that helps to im-prove the quality of the learning. After the end ofthe semester, we asked the participants to fill out aquestionnaire which consisted of three parts: usabil-ity experience questions, learning quality questionsand open questions for collecting the qualitative feed-backs. We collected 9 questionnaires that were filledout completely. They show us emergent problems anddirections for the future.

In the first part of the questionnaire we includedquestions recommended by System Usability Scale(SUS) (Lewis and Sauro, 2009) system to grade theusability of SlideWiki. SUS is a standardized, sim-ple, ten-item Likert scale-based questionnaire9 givinga global view of subjective assessments of usability. Ityields a single number in the range of 0 to 100 whichrepresents a composite measure of the overall usabil-ity of the system. The results of our survey showed

9www.usabilitynet.org/trump/documents/Suschapt.doc

a mean usability score of 67.2 for SlideWiki whichindicates a reasonable level of usability.

The second part of the questionnaire aimed to de-termine whether the SlideWiki helps to improve thequality of learning. It consisted of four questionswith five options from “absolutely agree (1)” to “ab-solutely disagree (5)”. The evaluation results for thesetwo parts are presented in Figure 6.

Although the positive answers prevail, we werenot satisfied by the fact that for many questions a thirdof participants chose the neutral value. It could be asignal, that students do not completely understand thequestion or are not 100% sure about the result.The lastpart of the questionnaire helped us to understand thereasons. We included four open questions:

1. What did you like most about Slidewiki?

2. What did you like least about Slidewiki?

3. What can we do to improve the Slidewiki’s usability?

4. What features would you add to Slidewiki?

Within the answers we found repeated complaints aboutseveral bugs, that interfered the working process. We con-sider this fact to be the main reason of neutral and contradic-tory values. However, we collected also positive opinions,especially about features and possibilities that SlideWiki al-lows. Three of the recipients mentioned that they mostlyliked that SlideWiki is easy to use, four of them noted, thatthey liked the idea of collaborative work and sharing thepresentations itself. Within the collected answers we alsogot important suggestions, which could be roughly dividedinto two groups:

• Suggestions about desired improvements of existingfeatures such as displaying the test results graphically,supporting more import formats, improving the SVGeditor etc.

• Suggestions about totally new features, several of thosewere later implemented, e.g. translation, templates forpresentation structure, etc.

Also we collected a few suggestions about features thatwere already implemented, but users were not aware ofthem. This encourages us to improve the documentation aswell as to enhance the simplicity and clearness of the userinterface. One of the students drew our attention to securityissues.

The results of our evaluation showed that our concept isclear to the users, they like this way of learning, storing andsharing of the presentations. However, we need to improvethe user interface, fix some minor bugs and spend more ef-fort on privacy and security issues.

6 Conclusions and future work

In this paper we presented the CrowdLearn concept thatapplies collaborative authoring and crowd-sourcing tech-niques to the creation of (semi-) structured e-learning con-tent. The concept is based on the SCORM concepts anduses the novel WikiApp data model to organize the con-tent closely aligned with the standard. We implementedand evaluated the concept with SlideWiki – a social webe-learning application targeting slide presentations and e-assessments. While the evaluation results were promising,we still need to extend the concept in the future to addressthe requirements requested by users.

Beside the usability improvements, our first directionfor future work is to implement a completely SCORM-compliant LMS and authoring tool, based on the SlideWiki.This will allow us to exchange the content with otherSCORM-compliant LMSs. Also, in a real e-learning sce-nario, learners come from different environments, havedifferent ages and educational backgrounds. These het-erogeneities in user profiles are crucial to be addressedwhen enhancing the CrowdLearn concept. New approachesshould provide the possibility to personalize the learningprocess. Thus, our second direction is providing the person-alized content based on initial user assessments. The thirddirection for the future work is to support the annotationof learning objects using standard metadata schemes. Weaim to implement the LRMI10 metadata schemes to facili-tate end-user search and discovery of educational resources.

Acknowledgement

We would to thank the AKSW research group membersfor their support during the evaluation of SlideWiki. Thiswork was supported by a grant from the European Union’s7th Framework Programme provided for the project LOD2

10Learning Resource Metadata Initiative: www.lrmi.net/

(GA no. 257943) and by a grant from the Saxon StateMinistry for Higher Education, Research and the Arts(SMWK) and the Development Bank of Saxony (SAB) forthe eScience project (grant no. 080951807).

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