The number of search blocks impacts search quality: fewer blocks yield higher sensitivity and lower precision¶

Claim · All claims
Evidence · 1 study · review r3 · q2
Currency · newest study 2018 · not yet checked against its sources · not reviewed by a person

Subclaims¶

q2 i? Across the included studies, search strategies with fewer search blocks retrieved more hits, showing higher sensitivity and lower precision, suggesting block count drives the sensitivity-precision trade-off. → Mette Brandt Eriksen 2018

Evidence¶

Mette Brandt Eriksen 2018¶

Mette Brandt Eriksen, PhD; Tove Faber Frandsen, PhD. (2018). The impact of patient, intervention, comparison, outcome (PICO) as a search strategy tool on literature search quality: a systematic review. Journal of the Medical Library Association 106 (4). https://doi.org/10.5195/jmla.2018.345

q2 · i? · review · r3

The review's cross-study synthesis of the PIC-versus-PICO and PICO-versus-PICOS/SPIDER comparisons: the three-block PIC strategy showed higher sensitivity and lower precision than four-block PICO, matching the pattern where PICO (three blocks) outperformed four-block PICOS and six-block SPIDER on sensitivity. The review also notes "the more search blocks that are included, the more restricted the search output will be."

"Taken together, these results suggest that the number of search blocks impacts the quality of the search output as quantified by sensitivity and precision."

Discussion¶

Related Claims¶

• The recommendation to avoid outcome-related search terms to preserve sensitivity is not substantiated by available evidence — related
• Only three studies assessing PICO as a search strategy tool were eligible for review, and heterogeneity prevented quantitative analysis — related
• PICO versus truncated PIC in PubMed: PICO showed higher median sensitivity and precision on the first 40 records, but PIC showed higher sensitivity on the full output — related
• PICO versus PICOS and SPIDER: PICO gave higher sensitivity and lower precision, but with different numbers of search blocks per model — a narrower finding that bears on this claim
• In a randomized crossover trial, PICO searching yielded higher average sensitivity and lower average precision than unguided searching, not statistically significant — related