Flowchart outlining study selection process. The study process is comprised of four steps: identification, screening, eligibility and final inclusion. Identification of studies will be primarily through the electronic literature search. Screening will involve title screening and removal of duplicate records. Assessing eligibility will involve three steps: phase one abstract screening (applying the primary selection criteria), phase two abstract screening (applying the secondary selection criteria) and full-text screening. Studies that pass all phases of eligibility screening will be included in the review.