In this chapter, we focus on the review PICO and the PICO for each synthesis as a basis for specifying which studies should be included in the review and planning its syntheses. In Chapter 2, Section 2.3, we introduced the ideas of a review PICO (on which eligibility of studies is based), the PICO for each synthesis (defining the question that each specific synthesis aims to answer) and the PICO of the included studies (what was actually investigated in the included studies). Decisions about which studies to include (and exclude), and how they will be combined in the review’s synthesis, should be documented and justified in the review protocol.Ī distinction between three different stages in the review at which the PICO construct might be used is helpful for understanding the decisions that need to be made. This chapter describes the processes by which the structure of the synthesis can be mapped out at the beginning of the review, and the interplay between the review question, considerations for the analysis and their operationalization in terms of eligibility criteria.
#Cross dj 3.2.2 how to
This will involve making plans for how to group variants of the PICO elements for synthesis. For example, the same intervention may be studied in the same population for different purposes or a review may specifically address the adverse effects of an intervention used for several conditions (see Chapter 19).Įligibility criteria do not exist in isolation, but should be specified with the synthesis of the studies they describe in mind. It should be noted that some reviews do legitimately restrict eligibility to specific outcomes. Outcomes usually are not part of the criteria for including studies, and a Cochrane Review would typically seek all sufficiently rigorous studies (most commonly randomized trials) of a particular comparison of interventions in a particular population of participants, irrespective of the outcomes measured or reported. The population, interventions and comparators in the review question usually translate directly into eligibility criteria for the review, though this is not always a straightforward process and requires a thoughtful approach, as this chapter shows.
#Cross dj 3.2.2 plus
Eligibility criteria are based on the PICO elements of the review question plus a specification of the types of studies that have addressed these questions.
When developing the protocol, one of the first steps is to determine the elements of the review question (including the population, intervention(s), comparator(s) and outcomes, or PICO elements) and how the intervention, in the specified population, produces the expected outcomes (see Chapter 2, Section 2.5.1 and Chapter 17, Section 17.2.1).
One of the features that distinguishes a systematic review from a narrative review is that systematic review authors should pre-specify criteria for including and excluding studies in the review (eligibility criteria, see MECIR Box 3.2.a). Cochrane Handbook for Systematic Reviews of Interventions version 6.2 (updated February 2021). In: Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, Welch VA (editors). Chapter 3: Defining the criteria for including studies and how they will be grouped for the synthesis. Review authors should plan at the protocol stage how the different populations, interventions, outcomes and study designs within the scope of the review will be grouped for analysis.Ĭite this chapter as: McKenzie JE, Brennan SE, Ryan RE, Thomson HJ, Johnston RV, Thomas J. Critical and important outcomes should be limited in number and include adverse as well as beneficial outcomes. It is rare to use outcomes as eligibility criteria: studies should be included irrespective of whether they report outcome data, but may legitimately be excluded if they do not measure outcomes of interest, or if they explicitly aim to prevent a particular outcome.Ĭochrane Reviews should include all outcomes that are likely to be meaningful and not include trivial outcomes. The population, intervention and comparison components of the question, with the additional specification of types of study that will be included, form the basis of the pre-specified eligibility criteria for the review. The acronym PICO (population, interventions, comparators and outcomes) helps to serve as a reminder of these. The scope of a review is defined by the types of population (participants), types of interventions (and comparisons), and the types of outcomes that are of interest.
0 kommentar(er)
