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Information Retrieval


Admission requirements

Basic prior knowledge of data structures, machine learning, probability theory, text representation (embeddings), linear algebra (vector spaces) is recommended. For students starting in February, it is advised to take this course in the second year of the master and not in the first semester.


Search engines, the internet and cheap powerful hardware have drastically changed the way humans deal with information. Whereas thirty years ago librarians were still classifying books and articles using subject codes, nowadays search technology is available to everyone, everywhere, and in many different contexts. We all use search engines on a daily basis to find relevant information. Not only on the web (e.g. with Google or chatGPT), but also in e-commerce websites (e.g., social media platforms (e.g. Twitter), travel portals (e.g. Booking), entertainment apps (e.g. Spotify), and our email clients. This course covers both the theory and practice of the field of Information Retrieval, with a focus on textual content.

1. Introduction
2. Evaluation and test collections
3. Boolean retrieval, indexing and compression

4. Vector space model
5. Neural IR and Transformers for ranking 1
6. Probabilistic models for ranking
7. Generative language models for IR
8. (student presentations about critical review of research paper)
9. Neural IR and Transformers for ranking 2

10. Web search and recommender systems
11. User interaction and conversational search
12. Guest lecture (IR/RecSys in practice)
13. Domain-specific IR

Course objectives

By the end of the course, the student should have a thorough understanding of:

  • the foundations of information retrieval models

  • evaluation methods for IR systems

  • efficient data structures and complexity of search and indexing algorithms

  • machine learning for ranking

  • technologies and relevance models for web search

  • applications and challenges of IR

  • reviewing a scientific IR publication

In addition, the student should have some practical experience with IR experiments using Python packages.


The most recent timetable can be found at the Computer Science (MSc) student website.

You will find the timetables for all courses and degree programmes of Leiden University in the tool MyTimetable (login). Any teaching activities that you have sucessfully registered for in MyStudyMap will automatically be displayed in MyTimeTable. Any timetables that you add manually, will be saved and automatically displayed the next time you sign in.

MyTimetable allows you to integrate your timetable with your calendar apps such as Outlook, Google Calendar, Apple Calendar and other calendar apps on your smartphone. Any timetable changes will be automatically synced with your calendar. If you wish, you can also receive an email notification of the change. You can turn notifications on in ‘Settings’ (after login).

For more information, watch the video or go the the 'help-page' in MyTimetable. Please note: Joint Degree students Leiden/Delft have to merge their two different timetables into one. This video explains how to do this.

Mode of instruction

Lectures, homework exercises, literature, assignments (no lab sessions).

Assessment method

The course grade will be computed as follows:

  • Homework (weekly exercises, individual) – 10%
  • Critical review of a scientific paper (in groups) – 10%
  • Practical assignment (in groups) – 20%
  • Final written exam (closed book) – 60%

The grade of the homework exercises is based on the number of completed exercises (n_completed/n_total∗10). Because the purpose is exercising, not testing, the homework exercises are not graded, only checked for completion.

Completion of exercises and assignments is not mandatory for passing the course, but the grade for exercises or assignments that are not submitted is 0.

The grade for the exam needs to be at least 5.5 to pass the course. The exam has a regular written re-sit opportunity. The teacher will inform the students how the inspection of and follow-up discussion of the exams will take place.

Reading list

Both textbooks are publicly available online.

  • Christopher D. Manning, Hinrich Schütze, and Prabhakar Raghavan (2008): Introduction to information retrieval. Cambridge University Press. ISBN: 978-0521865715

  • Jimmy Lin, Rodrigo Nogueira, and Andrew Yates (2021): Pretrained Transformers for Text Ranking: BERT and Beyond. Morgan & Claypool

  • Additional literature will be distributed on Brightspace.


From the academic year 2022-2023 on every student has to register for courses with the new enrollment tool MyStudyMap. There are two registration periods per year: registration for the fall semester opens in July and registration for the spring semester opens in December. Please see this page for more information.

Please note that it is compulsory to both preregister and confirm your participation for every exam and retake. Not being registered for a course means that you are not allowed to participate in the final exam of the course. Confirming your exam participation is possible until ten days before the exam.

Extensive FAQ's on MyStudymap can be found here.