Search and recommender systems

Publication activity

2019

1,696

2020

1,927

2021

1,874

2022

1,888

2023

2,265

2024

4,234

2025

7,700

Matches include papers applying these methods. Search precision and recall have not been systematically measured.

Title and abstract matches for articles, preprints and reviews; retracted work is excluded. Versions and overlapping areas may be counted more than once.

("information retrieval" OR "learning to rank" OR "dense retrieval" OR "neural retrieval" OR "retrieval augmented generation" OR "retrieval augmented language model")

Retrieved 2026-09-26.

Publishing authors

Base scenario: 9.4k publishing authors. Paper count × 3.64 known authors per paper ÷ 3 papers per author per year. The range assumes 1–5 papers per author; the base and both ends of the range are at least the 3,564 distinct Author IDs already observed in the sample.

The publication rate is an assumption, not a measured rate for this field. The range is a scenario, not a confidence interval.

Random sample: 1,000 of 7,700 papers (13.0%). 12.1% of authorship records lack an Author ID; 9.9% of retrieved works lack an abstract. Retrieved 2026-09-26.

Mean known authors per paper: 3.64; 95% bootstrap interval 3.45–3.87. This describes sampling variability, not search accuracy or uncertainty in the number of researchers.

Applied coauthors are included. Missing or incorrectly linked author records affect these figures. They do not measure research jobs or everyone working in a field.

Private investment

An assumed allocation of broader investment segments. The range is 0.5–2× the base case. Shares are editorial assumptions, not measured deals or research spending.

Base case: $4.92B.

• Data management, processing: $31.6B × 8.00%
• Marketing, digital ads: $2.51B × 10.00%
• Retail: $4.10B × 20.00%
• Legal tech: $3.79B × 35.00%

Company investment, not revenue or research spending. Ranges are scenarios, not confidence intervals.

Scope and related research

RAG is one part of the broader information-retrieval field.

Publication activity

2019

2,637

2020

3,119

2021

3,493

2022

3,876

2023

4,603

2024

5,826

2025

7,465

Matches include papers applying these methods. Search precision and recall have not been systematically measured.

Title and abstract matches for articles, preprints and reviews; retracted work is excluded. Versions and overlapping areas may be counted more than once.

("recommender system" OR "recommendation system" OR "sequential recommendation" OR "generative recommendation" OR "collaborative filtering")

Retrieved 2026-09-26.

Publishing authors

Base scenario: 7.5k publishing authors. Paper count × 3.01 known authors per paper ÷ 3 papers per author per year. The range assumes 1–5 papers per author; the base and both ends of the range are at least the 2,912 distinct Author IDs already observed in the sample.

The publication rate is an assumption, not a measured rate for this field. The range is a scenario, not a confidence interval.

Random sample: 1,000 of 7,465 papers (13.4%). 14.9% of authorship records lack an Author ID; 16.1% of retrieved works lack an abstract. Retrieved 2026-09-26.

Mean known authors per paper: 3.01; 95% bootstrap interval 2.87–3.15. This describes sampling variability, not search accuracy or uncertainty in the number of researchers.

Applied coauthors are included. Missing or incorrectly linked author records affect these figures. They do not measure research jobs or everyone working in a field.

Private investment

An assumed allocation of broader investment segments. The range is 0.5–2× the base case. Shares are editorial assumptions, not measured deals or research spending.

Base case: $2.92B.

• Marketing, digital ads: $2.51B × 20.00%
• Retail: $4.10B × 50.00%
• Entertainment: $3.66B × 10.00%

Company investment, not revenue or research spending. Ranges are scenarios, not confidence intervals.

Scope and related research

Advertising auctions and bidding are listed separately, although the methods overlap.

Publication activity

2019

63

2020

102

2021

93

2022

132

2023

116

2024

129

2025

160

Matches include papers applying these methods. Search precision and recall have not been systematically measured.

Title and abstract matches for articles, preprints and reviews; retracted work is excluded. Versions and overlapping areas may be counted more than once.

("click through rate prediction" OR "conversion rate prediction" OR "computational advertising" OR "real time bidding" OR "ad auction" OR "advertising attribution")

Retrieved 2026-09-26.

Publishing authors

443 distinct OpenAlex Author IDs across all 160 matching papers. This is an observed count within the query result; no publication-rate assumption is used.

Full query result: 160 of 160 papers (100.0%). 6.8% of authorship records lack an Author ID; 21.2% of retrieved works lack an abstract. Retrieved 2026-09-26.

Applied coauthors are included. Missing or incorrectly linked author records affect these figures. They do not measure research jobs or everyone working in a field.

Private investment

An assumed allocation of broader investment segments. The range is 0.5–2× the base case. Shares are editorial assumptions, not measured deals or research spending.

Base case: $1.63B.

• Marketing, digital ads: $2.51B × 65.00%

Company investment, not revenue or research spending. Ranges are scenarios, not confidence intervals.

Scope and related research

Draws on ranking, causal inference, and mechanism design.