(Week 5) [T9-2] Information Retrieval

Question 1

Explain the steps of evidence-based medicine. What has changed today?

Answer 1

1. Phrasing a clinical question that is pertinent and answerable.
2. Identifying evidence (studies in articles).
3. Critically evaluate the evidence to determine weather it applies to the patient.

Now, EBM puts less emphasis on critically evaluate original evidence. More emphasis on synthesized evidence readily available to clinicians (usually through electronic sources).

Question 2

What is information retrieval? What is the focus today?

Answer 2

Field concerned with the structure, analysis, organization, storage, searching, and retrieval of information.

In the healthcare, the initial focus was biomedical literature. Nowadays, it’s used all kinds of health data (molecular, images, videos, EHR, PHR).

Question 3

What is query formulation?

Answer 3

Return documents that satisfy a Boolean expression.

But what can we do when millions of documents satisfy the condition?
Use relevance and similarity.

Question 4

Differentiate relevance and similarity.

Answer 4

Relevance: measure of the importance of a document to the user who makes the search (subjective).
- 2 users give the same query and judge relevance of results differently.
- A document relevant today may become irrelevant in the future.

Similarity: measure of the “distance” between 2 documents (formula).

Question 5

How many models there are for main search in IR?

Answer 5

1. Boolean.
2. Ranked retrieval.
3. Vector space model.