How to Learn Information Retrieval
A structured path through Information Retrieval — from first principles to confident mastery. Check off each milestone as you go.
Information Retrieval Learning Roadmap
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Text Processing Fundamentals
1-2 weeksLearn the basics of text preprocessing: tokenization, stop word removal, stemming, lemmatization, and normalization. Understand how raw text is transformed into a form suitable for indexing and retrieval.
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Indexing and Data Structures
1-2 weeksStudy inverted indexes, posting lists, index compression, and how large-scale search systems efficiently store and access term-document mappings. Build a simple inverted index from scratch.
Classical Retrieval Models
2-3 weeksExplore the Boolean retrieval model, the vector space model with TF-IDF weighting, and cosine similarity ranking. Understand the trade-offs between exact matching and ranked retrieval.
Probabilistic and Language Models
2-3 weeksStudy the probabilistic retrieval framework, BM25, and query likelihood language models. Learn about smoothing techniques and how probabilistic models formalize the notion of relevance.
Evaluation Metrics and Methodology
1-2 weeksMaster precision, recall, F1, MAP, NDCG, and the Cranfield evaluation paradigm. Learn how TREC campaigns benchmark retrieval systems and the role of relevance judgments.
Query Processing and Feedback
1-2 weeksStudy query expansion, relevance feedback (Rocchio algorithm), pseudo-relevance feedback, and query reformulation techniques. Understand how user interaction can improve retrieval quality.
Web Search and Link Analysis
2-3 weeksExplore web crawling, PageRank, HITS algorithm, anchor text analysis, and the unique challenges of web-scale retrieval including spam detection and duplicate content handling.
Neural and Modern IR
3-4 weeksStudy neural ranking models (BERT-based re-rankers, dense retrieval with dual encoders), learned sparse representations, and retrieval-augmented generation. Explore current research frontiers and practical applications.
Explore your way
Choose a different way to engage with this topic — no grading, just richer thinking.
Explore your way — choose one: