The Difference Between Narrative Review and Systematic Review

Narrative Review vs Systematic Review

Both systematic and narrative reviews are classified as secondary research studies since they both use existing primary research studies e.g. case studies. Despite this similarity, there are key differences in their methodology and scope. The major differences between them lie in their objectives, methodology, and application areas.

Differences In Objective

The main objective of a systematic review is to formulate a well-defined research question and use qualitative and quantitative methods to analyze all the available evidence attempting to answer the question. In contrast, narrative reviews can address one or more questions with a much broader scope. The efficacy of narrative reviews is irreplaceable in tracking the development of a scientific principle, or a clinical concept. This ability to conduct a wider exploration could be lost in the restrictive framework of a systematic review.

Differences in Methodology

For systematic reviews, there are guidelines provided by the Cochrane Handbook, ROSES, and the PRISMA statement that can help determine the protocol, and methodology to be used. However, for narrative reviews, such standard guidelines do not exist. Although, there are recommendations available.

Systematic reviews comprise an explicit, transparent, and pre-specified methodology. The methodology followed in a systematic review is as follows,

1. Formulating the clinical research question to answer (PICO approach)
2. Developing a protocol (with strict inclusion and exclusion criteria for the selection of primary studies)
3. Performing a detailed and broad literature search
4. Critical appraisal of the selected studies
5. Data extraction from the primary studies included in the review
6. Data synthesis and analysis using qualitative or quantitative methods [3].
7. Reporting and discussing results of data synthesis.
8. Developing conclusions based on the findings.

A narrative review on the other hand does not have a strict protocol to be followed. The design of the review depends on its author and the objectives of the review. As yet, there is no consensus on the standard structure of a narrative review. The preferred approach is the IMRAD (Introduction, Methods, Results, and Discussion) [2]. Apart from the author’s preferences, a narrative review structure must respect the journal style and conventions followed in the respective field.

Differences in Application areas

Narrative reviews are aimed at identifying and summarizing what has previously been published. Their general applications include exploring existing debates, the appraisal of previous studies conducted on a certain topic, identifying knowledge gaps, and speculating on the latest interventions available. They are also used to track and report on changes that have occurred in an existing field of research. The main purpose is to deepen the understanding in a certain research area. The results of a systematic review provide the most valid evidence to guide clinical decision-making and inform policy development [1]. They have now become the gold standard in evidence-based medicine [1].

Conclusion

Although both types of reviews come with their own benefits and limitations, researchers should carefully consider the differences between them before making a decision on which review type to use.

References

1. Aromataris E, Pearson A. The systematic review: an overview. AJN. Am J Nurs. 2014;114(3):53–8.
2. Green BN, Johnson CD, Adams A. Writing narrative literature reviews for peer-reviewed journals: secrets of the trade. J Chiropratic Medicine 2006;5:101–117.
3. Linares-Espinós E, Hernández V, Domínguez-Escrig JL, Fernández-Pello S, Hevia V, Mayor J, et al. Metodología de una revisión sistemática. Actas Urol Esp. 2018;42:499–506.