This paper suggests the new term search-resistant concepts for concepts that are not searchable because of human’s lack of knowledge regarding the concept, poor reporting of the concept and lack of standard terminology for the concept. It suggests five solutions for dealing with such concepts.

Most evidence synthesis projects involving systematic reviewing need a written protocol containing a detailed or brief description of the main review question and its concepts.1 To formulate an answerable question, it is recommended that reviewers follow one of the established frameworks2 that guides them through a better definition and understanding of the review question. The most used framework is known as the PICOS acronym, which stands for its components or concepts: patient, problem or population (P), intervention or index test (I), control or comparison (C), outcome (O) and study design (S). This framework has some limitations,3 and since one size does not fit all and depends on the type of review, study designs and specific needs, many other frameworks and their acronyms have been developed.2 4 While such frameworks help structure the review question, protocol and final report, they are often not followed in the search step of the systematic review.

Designing the search methods usually requires a framework-based protocol, and writing the search methods is usually the last part of protocol development for the reviews because the search strategies are a translation of review questions into the syntax that information retrieval (search) systems could read and run. The main deviation in search design …