“Efficiency studies of the sharia insurance industry: A systematic literature review”

The sharia insurance industry has experienced significant development from year to year. A sharia insurance company’s efficiency is crucial because it reflects its capacity to generate outputs from resources. This study aims to enhance comprehension of the efficiency of sharia insurance currently studied by doing a comprehensive literature study. This study selected 429 published articles about Islamic insurance indexed by Scopus between 2010 and 2022. 32 final articles that met the criteria that discussed efficiency as the primary study included in the qualitative synthesis analysis were selected. As a result, this study succeeded in revealing the development of sharia insurance efficiency studies based on the number of publications, authors, countries, subject areas, sources of publications, and cited articles. The study found four main methods researchers used to measure the efficiency of Sharia insurance. This study also revealed several studies comparing the efficiency level between conventional and sharia insurance. Furthermore, the study’s results were mapped based on the significance of the influence of variables on the efficiency of Sharia insurance. This study offers a new opportunity for further development in methods and variables of the efficiency of sharia insurance.


INTRODUCTION
Sharia financial institutions are one of the economic driving forces in a country with a predominantly Muslim population (Mensari & Dzikra, 2017).Insurance is a financial institution that makes customers feel financially secure when something unexpected happens (Wahyono et al., 2021).For example, money is back when the insured item is damaged (Nugroho et al., 2021).From the sharia perspective, insurance is an effort to help each other between companies and group participants to help individuals who need assistance (Hasan, 2014).Unlike conventional insurance, which uses the concept of risk transfer, the insurer binds himself to the insured with a premium to be used by the insurer himself later.
In Arabic, sharia insurance, called Takaful, uses the concept of mutual help using a tabarru contract (Mahmuda & Azizah, 2019).Unfortunately, sharia insurance is still less attractive to the public.Hasibuan (2017) revealed that the growth of premiums, assets, claims, and conventional insurance investments in 2011-2015 had a higher increase than in the same period of sharia insurance.In addition, the market penetration of sharia insurance is also low (Maf'ula & Mi'raj, 2022).The consideration of potential insurance customers is the excel-lent performance of the institution due to high efficiency.Insurance companies should be innovative in managing their inputs and outputs so that current performance is manageable (Nurbaya & Alam, 2019).Optimizing the input and output is efficient (Iskandar et al., 2020).Efficiency becomes a reference for sharia financial institutions to determine whether a company's performance has been optimal.
There is a lot of research and studies about sharia insurance.So it is necessary to map out all of the literature related explicitly to efficiency studies in the sharia insurance industry to see the extent of the development of the study and to look for further opportunities.

LITERATURE REVIEW
A literature review is a critical study that can contribute to subsequent research design.Several previous researchers have conducted literature reviews on Sharia insurance studies.Sadeghi (2010) conducted a literature survey on sharia insurance to determine the emergence and evolution of sharia insurance.The study of Sadeghi (2010) highlighted the urgency of Takaful as a conventional alternative by discussing and comparing them.Olorogun and Noor (2014) also applied the literature survey method and described how the sharia insurance literature could influence standards and shape professional outcomes in the area of sharia insurance.Unfortunately, as a result, many studies disagree with each other and cause the curriculum in the sharia insurance profession to not exist at the national or international level (Olorogun & Noor, 2014).
Al-Amri and Hossain (2015) used a literature survey covering aspects of the concept and practice of sharia insurance.The study has limitations from the beginning of the emergence of sharia insurance until 2014 and states that today's sharia insurance practice is an alternative to conventional insurance.In contrast to the previous literature, the sharia insurance study of Khan et al. (2020) used bibliometric methods and content analysis.The literature of 69 articles at the beginning of 2020 was analyzed using the HistCite and VOSviewer software.As a result, the role of conventional insurance in building the economy is quite reasonable for sharia insurance to get the same effect.
In the following year, Kusmayadi et al. (2021) did the same research with the same method.The difference lies in the limitation of articles from 2014-2021 with the "dimensions.ai"database.The data obtained amounted to 500 articles, with 79.8% published in journals.As a result, the development of sharia insurance research from year to year has grown.From the conventional side, bibliometric research discussed the purity and progress of the sustainable life insurance business (Nobanee et al., 2021).
Several bibliometric studies on Sharia insurance (Alshater et al., 2021;Khan et al., 2020;Kusmayadi et al., 2021) showed considerable attention from researchers around efficiency studies as part of the performance of the Sharia insurance industry.A systematic literature review in the field of Sharia insurance was only conducted by Ansari (2022) but has yet to discuss in detail and in-depth about efficiency studies.
Studies on efficiency measurement in the takaful industry have been carried out by many researchers using a variety of methods such as Data Envelopment Analysis (Almulhim,  The previous study can be said to be similar to this study.The results of classifying themes from previous studies need to be arranged in synthesis.The analysis compiled by the synthesis can make it easier for the reader to find specific keywords.The sys-tematic literature review study examines the entire sharia insurance efficiency literature indexed in the Scopus database. For this reason, the study aims to describe the development of sharia insurance efficiency studies (based on the number of publications, authors, countries, subject areas, publication sources, and article citations) and to map the findings according to the existing variables of Takaful efficiency studies.

METHOD
This study is a type of qualitative with an SLR.This method can also show how extensive the study has been and provide an overview of different undisciplined studies (Rohman et al., 2021).In addition, this method differs from the usual literature method in that it needs to be objectively oriented, comprehensive, and sometimes similar to empirical studies (Weed, 2005).

Figure 1. PRISMA process in article selection
This study used PRISMA statements to help flow the process of selecting, accepting, or rejecting articles.PRISMA is an evidence-based minimum item for reporting in systematic reviews and meta-analyses (Moher et al., 2009).The statement is a guide for setting the planned review's reasons, hypotheses, and methods.That way, this study can ensure that reporting is transparent and complete.The database used in this study is Scopus, one of the largest indexing sites for reputable publications (Ahmi et al., 2019;Boonroungrut et al., 2022;Jeflea et al., 2022).
Using the Scopus database, the authors searched the literature with the keywords "Islamic insurance" OR "takaful" OR "sharia insurance" from the search box.429 articles related to these keywords were found on March 16, 2022.Then, a search for keywords that used the most "efficiency" was conducted according to the topic to be analyzed.The remaining 44 articles have been selected with indications discussing efficiency in sharia insurance.Then, from 44 articles, the second stage of selection was carried out until 33 articles were found that were most suitable for analysis.The study chose these articles because they became efficient as a significant part of the study.In addition, all articles were checked manually for articles indicated as plagiarism results.This study has tried its best to contact the authors but has not received a response from one article.Finally, 32 articles can be downloaded for analysis at a later stage.

RESULTS
This study presents the results in two forms, namely the results of descriptive analysis and classification of publication themes about the efficiency of sharia insurance.
Figure 2 shows a graph of the development of publications on efficiency studies in sharia insurance or Takaful from year to year.Most publications occurred in 2018, with eight published articles.It was followed by a decrease in publications in 2019 with seven articles.In 2021, there was a third increase, with five articles published after a decline in 2020.In 2014, 2015, and 2020, publications averaged three articles per year.In addition, the number of publications could be more substantial at one article per year.
Table 1 describes the authors who most actively contributed to published articles according to the data of this study.First, Hui Shan Lee became a prolific writer who contributed four articles with a percentage of 18.2%, followed by Rubayah Yakob and Fan Fah Cheng with three articles and 13.6%.Table 1 also shows that the authors are predominantly from Malaysia.
Next, Table 2 shows the research subject areas in discussing and analyzing what they researched.Economics, Econometrics, and Finance became the highest subjects studied because they had a percentage of up to 38.89%.They were shortly followed by Business, Management, and Accounting with 37.04%.The topics of Arts and Humanities, Physics and Astronomy are far below with a percentage of 3.70%.In addition, other topics only have a percentage of 1.85%.
Table 3 shows the countries that are often the basis for publication.As the author said earlier, Malaysia is a country that publishes more than five publication articles, namely 19 articles, with a percentage of 45.24%.This finding is also in line with the article's author, who is predominantly   Publishing requires a responsible journal to be the "Home" of an article.Quantitative calculations using regression analysis are the third highlight in measuring the effi- There is also a study that uses an article-based theory library and content analysis to examine the sustainable efficiency of diversifying the drivers of sharia insurance for the benefit of the poor in Saudi Arabia (Hassan, 2019).This study is similar to a literature review because research gaps are found that encourage other researchers to be developed based on articles.In addition, there is conceptual-based research in addition to the above DEA conceptual research.An asymmetric ARCH model with a Skewed distribution is used to measure the Value at Risk (VaR) insurance market insurance in the Kingdom of Saudi Arabia (KSA).As a result, this method can estimate the ability of conventional and sharia insurance companies (Hasnaoui, 2018).Benyoussef and Hermit (2019) even compared sharia insurance with cooperative insurance companies, and sharia insurance is still relatively more efficient than cooperative insurance.However, in the KSA area, both companies still have the same efficiency in the management sector (Naushad et al., 2020).
Efficiency has a variable that becomes an indicator of a company to be analyzed and concluded, as shown in Table 7.Some of them have significant changes from the results of the analysis.For example, the scale of the board of directors, product specialization, and the company's scale become variables by producing significant changes and positively impacting cost efficiency.This data indicates that large companies are better optimized than smaller companies to realize their operational developments seen from the track record of the board of directors and financial experience (Kader et al., 2010)

DISCUSSION
According to this research's findings, the data envelopment analysis (DEA) method predominated the research analysis.Decision-Making Units (DMU), especially insurance companies, need to be re-examined against efficiency indicators of sharia insurance because they are a set of variables that can determine whether the economy is running well and efficiently or not.Human Capital variables also can significantly affect efficiency because they are the engine of the running of Sharia insurance companies.If the performance of the management is good, then the company's performance should also run efficiently.In addition, regulations that do not have a significant effect may not necessarily apply to other companies that have not been studied.Therefore, the study of regulations of Takaful companies is essential to be conducted.

CONCLUSION
This study tries to answer two research questions.How is the development of research on the efficiency of the Sharia insurance industry in terms of the trend of increasing publications, the most productive authors, subject areas, publication sources, countries, and citations?What are sharia insurance efficiency studies synthesized based on methods and findings?Research that measures efficiency in the Sharia insurance industry in the previous year with the current year has differences.2018 became the most active year for the emergence of Sharia insurance efficiency research and was dominated by Malaysia as the publication country.Hui Shan Lee is a researcher who often raises this issue, with the percentage reaching 18.2%.Then the subject area often used in this theme is "Economics, Econometrics, and Finance," and "The Academy of Accounting and Financial Studies Journal" is the most dominant journal for article publication.Then, the article "The cost efficiency of takaful insurance companies" has the best citations from other articles.This study found that the data of the four main methods in Sharia insurance efficiency studies include Data Envelopment Analysis, Stochastic Frontier Analysis, Malmquist Productivity Index, and Regression Analysis.In line with the conclusion above, this study also succeeded in synthesizing the results of Sharia efficiency research in comparison of efficiency and significant and insignificant variables that affect the efficiency of the Sharia insurance industry.

Figure 2 .
Figure 2. Publication trends by year

Table 2 .
Publications by subject area

Table 3 .
Publications by the country issuing five or more documents

Table 4 .
Publications by source title

Table 5
shows that the published articles the authors have prepared have many citations.The highest percentage of citations, with 21.31%, was achieved by an article entitled "The Cost Efficiency of Takaful Insurance Companies," with 52 citations.Meanwhile, the article entitled "Governance mechanisms and efficiency: Evidence from an alternative insurance (takaful) market" followed quite a distance with a percentage of 9.84% or 24 times cited.The article entitled "Cost efficiency and board composition under different takaful insurance business models" is slightly below it with 23 citations with a percentage of 9.43%.Several articles also followed with the distance between the number of citations not too far away.

Table 5 .
Top five most cited publications

Table 1 .
Top three most productive authors

Table 6 .
Efficiency analysis modelResearch on sharia insurance efficiency studies on the previous methods.Other literature addresses this issue with different styles.For example, Halim et al. (2020) used The Treynors and Sharpe's Ratio method to measure efficiency, referring to the profit ratio based on volatility, measuring standard deviation, and the level of investment profit.

Table 7 .
Influence of variables on efficiencyThe Scale Of The Board Of Directors Kader et al. (2010) The Users' Size and The Organization's Form Yakob et al. (2014a)