Objective: To describe a new process model of study identification specifically for randomized studies in systematic reviews of intervention effect.
Methods: Identification of studies is a critical step in the conduct of systematic reviews of effectiveness. The prevailing approach to study identification in systematic reviews, referred to as ‘The Conventional Approach,’ (Cooper et al., 2018) prioritizes bibliographic database searching as the primary method of study identification, followed by searches of grey literature including registers and conferences, and supplementary search methods. Studies and study reports identified by all of these methods are then pooled for study selection.
A new process model is proposed which separates the search for studies from the search for study reports, into distinct phases. We distinguish here between studies and study reports, the former being the focus of the first phase in this process model.
Results: The proposed three phase process model will be described and illustrated. The implications of early study identification in phase one, on the subsequent bibliographic database search in phase two, will be highlighted.
Conclusions: This new process model is an alternate to The Conventional Approach of study identification for use in complicated systematic reviews of intervention effectiveness.

References;
Cooper C, Booth A, Varley-Campbell J, Britten N, Garside R. Defining the process to literature searching in systematic reviews: a literature review of guidance and supporting studies. BMC Medical Research Methodology 2018;18(1)