Analysis or Review? How to Tell the Difference

When it comes time to summarize existing research in your field, the sheer volume alone can be daunting. Then, you must ask yourself a question: are you writing a review, or are you performing a meta-analysis? Does the difference even matter?

The short answer is: yes. On first glance, reviews and meta-analyses might seem quite similar; indeed, they are in a similar vein, but they are not the same type of report. A systematic review has a narrower scope and can be more subjective, while a literature review has a broad scope. A meta-analysis’ scope sits somewhere in the middle, and it is more objective by nature.

It should be noted that all reviews are not created equal. The main types of reviews are literature reviews and systematic reviews. Literature reviews collect key sources on a topic and discuss those sources. This may be a historical overview of a field, or a ‘round up’ of emerging changes. In the sciences, a literature review is also useful when reporting various methods, allowing the author to compare and contrast the benefits or drawbacks. A literature review can be included in a research paper or a case study as part of the background or introduction, particularly if the study is suggesting a new finding well outside the field’s norm or a new method to replace older ones.

A systematic review generally has a much narrower focus than a literature review, and a question is usually posed to which the author draws on past reports or case studies to provide evidence for an answer or solution. As the name implies, systematic or explicit methods are used to identify and appraise studies for inclusion within the review itself. The data is then extracted from these studies in order to answer a question through statistical analysis, whereas data extraction does not usually occur in a literature review.

Though this sounds quite similar to a meta-analysis, they’re not quite the same thing. A meta-analysis extracts data from previously reported studies and uses statistical analysis to summarize overall trends within the body of literature, rather than answer a specific question. It is possible for a meta-analysis to be part of a systematic review, but a systematic review cannot be a part of a meta-analysis. A meta-analysis, by its nature, is a more objective way to observe previously reported studies, while a systematic review may be critical.

So, as you sit to write, ask yourself a few questions. Are you writing a critique of existing methods, or documenting what has been published to introduce a new idea or contrasting results? Are you analyzing the data reported in previous studies and reporting trends, or using an analysis to answer a question? By answering these, you will be able to determine what type of manuscript you are looking to write, and you should be able to better choose your sources going forward.