Methods

Systematic review

A systematic review answers a defined question through planned, transparent methods for finding, selecting, appraising, and synthesizing relevant studies. Its credibility depends on those procedures and the evidence located. A review can be systematic without combining effects statistically, and a statistical synthesis is not a substitute for a sound review.

What does the relevant body of evidence show when studies are sought and assessed using explicit methods?

How it works

  1. Define the question, eligibility criteria, and review protocol. For intervention effects, specify population, intervention, comparison, and outcomes; use a framework suited to the question rather than forcing every review into PICO.
  2. Build and document a reproducible search across appropriate sources. Screen against the criteria, record reasons for important exclusions, and link multiple reports from the same study.
  3. Extract relevant evidence, assess risk of bias, and choose a synthesis that fits the studies. Report limitations of the search and evidence, with independent checking of consequential selection and extraction decisions.

Evidence: (Cochrane Handbook, Chapter 1: Starting a Review, n.d.); (Cochrane Handbook, Chapter 4: Searching for and Selecting Studies, n.d.)

Reviewing retrieval-practice interventions

Teaching scenario

Synthetic example: A seminar team proposes reviewing retrieval practice for delayed learning outcomes in undergraduates. It must decide whether classroom and laboratory studies answer the same question and whether immediate quizzes meet the delayed-outcome rule. One trial may have an article, a registry entry, and a thesis report; these should be linked rather than counted as three independent studies. This scenario specifies a review task, not a claim that retrieval practice works. Learners can audit the proposed search and eligibility decisions before any studies are screened.

This example is constructed for learning. It does not report an observed research result.

What can you conclude?

Provides an auditable account of a body of evidence and helps identify uncertainties and research gaps.

Evidence: (Cochrane Handbook, Chapter 1: Starting a Review, n.d.); (Cochrane Handbook, Chapter 4: Searching for and Selecting Studies, n.d.)

Limits and common mistakes

  • Even a careful review can miss unpublished or inaccessible evidence and inherit weaknesses of included studies.
  • Search methods and eligibility choices constrain the conclusion; a review label alone does not establish comprehensive coverage.

A mistake to catch

Calling a convenient reading list systematic, or counting several reports of one study as independent evidence.

Evidence: (Cochrane Handbook, Chapter 1: Starting a Review, n.d.); (Cochrane Handbook, Chapter 4: Searching for and Selecting Studies, n.d.)

Sources and inspection notes

Links checked October 21, 2026. Inspection scope is stated for each source; an access date is not a publication date.

  1. Cochrane handbook, chapter 1: Starting a review. (n.d.). https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current/chapter-01

    Sections 1.2–1.3, question formulation and team roles Official current intervention-review guidance. PICO applies to intervention questions, not automatically every psychology review. Opened and checked 21 October 2026.

  2. Cochrane handbook, chapter 4: Searching for and selecting studies. (n.d.). https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current/chapter-04

    Sections 4.2.2, 4.3, 4.6; searching, study/report distinction, selection Official current methods. Supports reproducible multisource searches and linking multiple reports of one study. Opened and checked 21 October 2026.

Keep reading

Spielman, R. M., Jenkins, W. J., & Lovett, M. D. (2020). Psychology 2e. OpenStax. https://openstax.org/books/psychology-2e/pages/2-3-analyzing-findings

Nearest related OpenStax Psychology 2e reading. This is a course connection, not evidence for every specialist detail above.

Specialist reading: Cochrane handbook, chapter 1: Starting a review. (n.d.). https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current/chapter-01

Related methods

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