Table 2

Tools and techniques for searching databases

Technique and descriptionCommandExample
All known synonyms and spellings of key wordsDoubly robust regression could also be referred to as doubly robust estimate
Replace up to one character in the word—allows alternative spellings to be included.?Mendelian randomi?ation would include Mendelian randomisation and Mendelian randomization
Truncation command—used to acknowledge and capture alternative endings to words.*Inverse probability weight* would additionally search for inverse probability weights and inverse probability weighting
Boolean logic operators—used to either: (a) identify results with at least one of the search terms present; and, (b) to combine results of different search terms.“OR”
Conduct problem* OR conduct disorder* would retrieve articles that have either terms.
Conduct problem* AND causal* would only retrieve articles that have both terms.
Proximity operators—used to identify words within a specified distance of each other.adj3Balancing adj3 covariate would identify articles whereby “balancing” and “covariate” are within three words of each other.