Wikipedia Quality Flaw Prediction

Wikimedia Deutschland

In previous years, we have addressed quality issues in Wikipedia in the form of vandalism detection. However, the majority of quality flaws is not caused due to malicious intentions but stem from edits by inexperienced authors; examples include poor writing style, unreferenced statements, or missing neutrality. This year, we generalize the vandalism detection task and focus on the prediction of quality flaws in Wikipedia articles.

We cast quality flaw prediction in Wikipedia as a one-class classification problem (as proposed in this paper). The key feature of this problem is that there is no representative "negative" training data (articles that are tagged to not contain a particular flaw), which makes common discrimination-based classification techniques, like binary or multiclass classification, inapplicable.

The task targets the ten most frequent quality flaws of English Wikipedia articles, which are listed in the following table. You can tackle each flaw individually, but you must predict all ten flaws. The prediction performance is evaluated individually for each flaw, and the results are averaged to a final score.

Flaw nameDescription
UnreferencedThe article does not cite any references or sources.
OrphanThe article has fewer than three incoming links.
RefimproveThe article needs additional citations for verification.
Empty sectionThe article has at least one section that is empty.
NotabilityThe article does not meet the general notability guideline.
No footnotesThe article’s sources remain unclear because of its inline citations.
Primary sourcesThe article relies on references to primary sources.
WikifyThe article needs to be wikified (internal links and layout).
AdvertThe article is written like an advertisement.
Original researchThe article contains original research.

Background. Wikipedia users who encounter some flaw can tag the article with a respective cleanup tag. The existing cleanup tags correspond to the set of quality flaws that have been identified so far by Wikipedia users and the tagged articles provide a source of human-labeled data (this idea has been proposed in this paper). Hence, each of the ten flaws is defined by the respective cleanup tag.

Remark. Since quality flaw prediction in Wikipedia is a one-class problem, the engineering of features that discriminate articles containing a certain flaw from all other articles is one of the primary challenges. You can use all features imaginable and any source of information (e.g., the articles' revision history, Wikipedia's link graph, and also external sources), with one exception: you must not use any information concerning the cleanup tags that define the flaws. I.e., to predict whether an article suffers from a certain flaw, you must not analyze whether the article is tagged with the respective cleanup tag nor whether it is a member of a respective cleanup category. Such features are unusable in practice.

Given a set of Wikipedia articles that are tagged with a particular quality flaw, decide whether an untagged article suffers from this flaw.

We are happy to announce the following overall winner of the 1st International Competition on Quality Flaw Prediction in Wikipedia who will be awarded 200,- Euro sponsored by Wikimedia Deutschland:

  • Edgardo Ferretti, Donato Hernández Fusilier, Rafael Guzmán Cabrera, Manuel Montes-y-Gómez, Marcelo Errecalde, and Paolo Rosso.

Training Corpus

To develop your approach, we provide you with a training corpus which comprises a set of Wikipedia articles for a number of quality flaws.

Learn more » Download corpus


For each set of articles per quality flaw, your quality flaw prediction software shall output a file formatted as follows:

279320 1 0.8647264878 5.0548156462 0.2854089458 ... 0.0000000584
871808 0 0.6442019751 3.4979755645 0.1203675764 ... 0.0505761605
850457 1 0.5054090519 9.3060661202 0.0550005005 ... 0.9190851616
912468 0 0.9644561645 1.5059164514 0.4696140241 ... 0.0000000031

  • The column PAGEID denotes the pageid of the test article.
  • The column C denotes the decision of your classifier. This value should be either 1 or 0, where 1 means the article contains the flaw.
  • The columns FEATUREVAL_1 to FEATUREVAL_n denote the n feature values of your document model for the given article. The feature values need not be normalized, and they should consist of unrounded values. If you have non-numeric features include them as well. Please send along a short description of each feature, and make sure that all entries in a column are based on the same feature implementation.
Performance Measures

The prediction performance will be judged by average precision, recall, and F-measure over all quality flaws.

Test Corpus

Once you finished tuning your approach to achieve satisfying performance on the training corpus, you should run your software on the test corpus.

During the competition, the test corpus does not contain ground truth data that reveals whether or not a suspicious document contains any plagiarized passages. To find out the performance of your software on the test corpus, you must collect the output its and submit it as described below.

After the competition, the test corpus is updated to include the ground truth data. This way, you have all the neccessary data to evaluate your approach on your own, without submitting it's output, yet being comparable to those who took part in the competition.

Download corpus


To submit your test run for evaluation, we ask you to send a Zip archive containing the output of your software when run on the test corpus to

Should the Zip archive be too large to be sent via mail, please upload it to a file hoster of your choosing and share a download link with us.


The following table lists the performances achieved by the participating teams:

Wikipedia quality flaw prediction performance
Precision Recall F1-measure Participant
0.735400 0.917097 0.814529 Edgardo Ferretti*, Donato Hernández Fusilier°, Rafael Guzmán Cabrera°, Manuel Montes-y-Gómez^, Marcelo Errecalde*, and Paolo Rosso†
* Universidad Nacional de San Luis, Argentina
° Universidad de Guanajuato, Mexico
^ Óptica y Electrónica (INAOE), Mexico
† Universidad Politécnica de Valencia, Spain
0.753213 0.852926 0.798336 Oliver Ferschke, Iryna Gurevych, and Marc Rittberger
Technische Universität Darmstadt, Germany
0.043209 0.579241 0.079449 Ionut Cristian Pistol and Adrian Iftene
"Alexandru Ioan Cuza" University of Iasi, Romania

A more detailed analysis of the detection performances can be found in the overview paper accompanying this task.

Learn more »

Related Work

Task Chair

Maik Anderka

Maik Anderka

Bauhaus-Universität Weimar

Task Committee

Benno Stein

Benno Stein

Bauhaus-Universität Weimar