A narrative review provides a synthesis or description of the literature review without using quantitative methods. Often the purpose of the review involves the evaluation of some set of investigations and involves theoretical statements and casts a wide range of topics and investigations.
The strengths of a narrative review are:
Unlike quantitative reviews, which have very narrowly defined parameters and precise inclusion and exclusion rules, a narrative review has more flexibility. The narrative review provides more potential for individual insight and opportunities for speculation than most quantitative review approaches.