Literature review vs systematic review: Know the key difference between them & get over the confusion

With an ever-increasing surfeit of researches being published, it is quite challenging for researchers to keep up with the literature. Therefore, reviews summarising the key results of various studies (in a specific domain) is an extremely efficient approach for acquiring the underlying details about what works and what doesn’t. 

Performing a critical review of literature is vital for research in any domain. It identifies the past research conducted on a specific topic, encapsulates, compares & contrasts various scholarly articles, books or any other relevant sources. 

Assessment of literature can be accomplished using various techniques including literature review(traditional), systematic review, narrative review, theoretical review, etc. However, most often it’s common for researchers to confuse among literature review and systematic review as both the methods are used to provide a summary of existing literature. But technically, both the approaches are quite different from each other.

Have a detailed look at literature review & systematic review 

• Literature review 

Literature review is the first step in addressing a research topic to an idea of the status of the specific research field for further study. Literature review also known as comprehensive review acquires all the necessary information on a specific topic in order to offer an overview of the available literature on a particular theme and find a gap between the two studies. In this process, the research sources are collected from various databases and qualitatively brought together. 

Getting started with a literature review process can be overwhelming. Some of the steps involved in achieving this process are:

1. Define the scope of your study - Determine the subject that interests you and choose an unidentified issue. This is followed by narrow downing the wide topic to focus on a specific theme. 

2. Identify the literature -  Begin this process by looking for literature sources broadly. Search from databases using keywords, scholarly books, journals such as Scopus, research articles, Google scholar, etc.

3. Critically evaluate the literature - Pay attention to key findings, methodologies, theories, conflicting ideas, etc. This will help you explore relationships, critical gaps and themes.

4. Organise the sources - Segregate available resources pertaining to your study as per their roles in addressing the research question. Yor can organise by chronology, theme, methodology, etc. 

Characteristics of literature review process

1. Outlines important or latest research trends

2. Analyses the strengths and weaknesses of the study

3. Identifies knowledge gap between two studies

4. Establishes a strong need for current study

• Systematic review 

Systematic review is a well-planned review process that looks at a research topic in depth using a scientific method. It not only evaluates the existing literature, but also assess grey literature, theses/dissertations, and abstracts/conference proceedings. Systematic review sources are considered to be the original work as they are performed using rigorous methodological methods. In this approach, in addition to the results of the searches, the search strategy, evaluation and interpretation of research are included. 

Beginning with systematic review process is indeed an arduous task. To accomplish this process, a researcher must follow several steps including:

1. Inclusion of research question - Begin with well-formulated question that aligns with the objectives and the methodology of the study. Prior to developing a question it is advisable to check if the research question exists or not. 

2. Identify studies - Utilise several sources to locate and retrieve studies. Ensure that the sources include grey literature, scientific conference papers, databases, etc. 

3. Evaluate studies - To determine the validity of the study, utilise specific criteria such as number of citations, year of publication, conflicting issues, etc.

4. Collect and analyse data - Group studies according to their methodological similarities. Describe methodological approaches such as variables, measures, samples, etc. This if followed by using statistical methods to integrate outcomes of results of systematic review.

Features of systematic review process

1. States set of objectives using pre-defined eligibility criteria for studies

2. Attempt to identify studies that meet the eligibility criteria

3. Assessment of the validity of the significant results

4. Synthesis and presents the results of the included studies

Difference between literature review and systematic review                        

Features	Literature review	Systematic review
Focus review	Introduces context, current thinking without a specific question	Utilises precise question to develop evidence to pinpoint a piece of research.
Data collection method	Identifies sources randomly and does not use grey literature in common	Uses specific keywords to identify sources and commonly uses grey literature
Data extraction method	Doesn’t involve any precise data extraction tool	Uses precise data extraction tool
Data analysis method	Researcher analysis by paying attention to theories, etc.	Referenced data analysis method including strength of evidence, etc.
Publication	Not suitable for journal publication	Suitable for journal publication
Results	Actions informed by evidence from included sources	Actions based on evidence from reviewed sources

Undertaking a review of the literature and selecting a suitable framework for the same decides the fate of your research. Therefore, understand the requirements of your study and choose the approach accordingly and wisely.