• Time
  On average, systematic reviews require 18 months of preparation.
   
• A systematic review team
  You need to work with subject experts to clarify issues related to the topic: information specialists or librarians to develop comprehensive search strategies and identify appropriate databases; reviewers to screen abstracts and read the full text; a statistician who can assist with data analysis; and a project leader to coordinate and write the final report.
   
• A clearly defined research question (PICO)
  Clarify the key question(s) of your systematic review and the rationale for each question. Use a framework such as PICO to identify key concepts or aspects of the question. 
   
• Orientation of the literature
  Orientation of the literature is relevant to (1) find reviews or protocols that are (partially) overlapping your research question and (2) find studies to include. You need to get an impression of the amount of studies relevant to the topic and the variation between relevant studies. Depending on what you find, you can finetune the eligibility criteria.
   
• Eligibility criteria (selection criteria)
  Eligibility criteria could be seen as a detailed explanation of the PICO. They should be finalized before starting with the next steps (search development and study selection). The eligibility criteria follow the structure of PICO (or other framework used) and also address the study design.
  For example: Articles will be eligible or inclusion in this review if they meet the following criteria: (1) the Study design is ...... (2) the Population is ... (3) the Intervention is .... (4) the Control group is... (5) the Outcomes are ..... 
   
• A protocol
  A systematic review protocol outlines the study methodology. The protocol should include the rationale for the systematic review, key questions broken into aspects or "PICO components", selection criteria, literature searches for published/unpublished literature, the process for study selection, data abstraction/data management, the workflow and tools used for assessing the methodological quality of individual studies, data synthesis, and grading the evidence.  Need help writing a protocol? See the University of Warwick's protocol template.
  Register your protocol in PROSPERO. Registration is free and open to anyone undertaking systematic reviews of the effects of interventions and strategies to prevent, diagnose, treat, and monitor health conditions, for which there is a health related outcome.
   
• Comprehensive literature searches
  Identify appropriate databases and conduct comprehensive and detailed literature searches that can be documented and duplicated.
  It is recommend to involve an information specialist. 
   
• Follow reporting guidelines
  Follow PRISMA Statement or other appropriate guidelines for reporting your review for publication.

A major cause of bias in a systematic review is answering a different question to that being originally asked. This is why it is important to develop a review plan or protocol.

The benefits of having a protocol before the beginning of a review:

• relate to the validity and merit of a research process that reduces risk of bias
• promotes a systematic rather than ad hoc approach to the review process
• facilitates communication with others and promotes consistency between review team members
• support the reliability and usefulness of reviews to health professionals

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA Statement)
The aim of the PRISMA Statement is to help authors improve the reporting of systematic reviews and meta-analyses. The focus of PRISMA is randomized trials, but it can also be used as a basis for reporting systematic reviews of other types of research, particularly evaluations of interventions.

Cochrane Collaboration Handbook
The Cochrane Handbook for Systematic Reviews of Interventions is the official document that describes in detail the process of preparing and maintaining Cochrane systematic reviews on the effects of healthcare interventions. This is Version 5.1.0 of the Handbook; last edited March 20, 2011.

Systematic Reviews: CRD’s Guidance for Undertaking Reviews in Health Care
Provides practical guidance for undertaking evidence synthesis based on a thorough understanding of systematic review methodology. Presents core principles of systematic reviews and highlights issues that are specific to reviews of clinical tests, public health interventions, adverse effects, and economic evaluations. The final chapter discusses incorporation of qualitative research in or alongside effectiveness reviews.

Finding What Works in Health Care: Standards for Systematic Reviews (IOM)
IOM's (2011) standards address the entire systematic review process, from locating, screening, and selecting studies for the review, to synthesizing the findings and assessing the overall quality of the body of evidence, to producing the final review report. Includes a link to the IOM Standards for Systematic Reviews.

Methods Guide for Effectiveness and Comparative Effectiveness Reviews (AHRQ)
This guide was developed to improve the transparency, consistency, and scientific rigor of those working on Comparative Effectiveness Reviews.

Campbell Collaboration
Guidelines for producing a Campbell Systematic Review. The Campbell Collaboration is an international research network that produces systematic reviews of the effects of social interventions.

Qualitative Research Guide
Online resources to aid in conducting, finding, using, synthesizing, and teaching qualitative research in health sciences.

3IE Impact
International Initiative for Impact Evaluation offers a database of systematic reviews on impact evaluations and has methods information for conducting your own.

Designed by Jessica Kaufman, Cochrane Consumers & Communication Review Group, Centre for Health Communication & Participation, La Trobe University, 2011. CC-BY-SA License.
Video: 'Exploring systematics reviews: what autors do'