The effect of religiosity on life satisfaction: A meta-analysis

21 articles quantitatively, and the systematic literature review (SLR) approach was used to narrate the development of issues concerning religiosity and life satisfaction in 40 articles. In general, this study succeeds in demonstrating that the influence of the religiosity variable on life satisfaction in various study samples is linear and has a positive effect. Contribution: The dimensions of religiosity and life satisfaction are still very limited to the characteristics of disciplines attached to researchers. This resulted in the dimension being repeatedly used (redundancy) in various studies, resulting in the second dimension of the issue (i.e., religiosity and life satisfaction) being less developed. Therefore, it contributes to the issues as a foundation of new directions, i.e., emic perspectives, in understanding the relationship between religiosity and life satisfaction.


Introduction
Religiosity directly impacts various aspects of human life and acts as a moderating variable, by strengthening or influencing multiple aspects of human life in either economic, educational, cultural or political domains (Gill et al. 2010). In this regard, religiosity influences psychological aspects at an individual level, that is, individual satisfaction with life. Religiosity, which involves theological orientation and the observance of religious practices and rituals, has an important role in influencing personal life satisfaction. Various social scholars have studied this dimension, and it has even been quantified (Hill & Hood 1999). It is possible to introduce a scale of religiosity measurement. Joshanloo (2021), in his study on religiosity and life satisfaction, discovered that the relationship between religiosity and life satisfaction occurred at the individual level. Plouffe and Tremblay (2017) found that religiosity and income influence personal life satisfaction at the individual level. Cohen et al. (2005) identified the effect of religiosity on life satisfaction via two dimensions of religiosity, namely, intrinsic and extrinsic religiosity. For life satisfaction, the relationship between these two dimensions is positive. Furthermore, Fard, Shahabi and Zardkhaneh (2013) discovered a broad and dynamic relationship between religiosity and life satisfaction. In this case, religiosity has an emotional effect on life satisfaction at the individual level. According to Fard et al. (2013), religiosity influences an aspect of life satisfaction, including social pleasure and marital satisfaction. Some of the research findings support the generally positive relationship between religiosity and life satisfaction. However, it is difficult to find a study accurately mapping various kinds of existing literature of the relationship and influence of religiosity on life satisfaction.
This study aims to fill such a gap in the existing literature while also providing a novel perspective through the following strategies: Firstly, by mapping the relationship between religiosity and life satisfaction using a meta-analysis approach. As described by Davis et al. (2014), a meta-analysis is useful for synthesising the results of previous research (Davis et al. 2014). The meta-analysis aims to synthesise at least 21 articles investigating the relationship between religiosity and life satisfaction. Secondly, synthesising various literature on the relationship between religiosity and life satisfaction. This study contributes to the development of literature on religiosity and life satisfaction through a systematic critical review. Snyder (2019) believed that a systematic literature review (SLR) approach could identify trends and even determine the direction of a research issue development. In this regard, the foci of this study are formulated to map the relationships among variables and synthesise the existing topics from the literature. A metaanalysis approach was selected, because through this method the consistency of the influence of religiosity on life satisfaction can be tested again. Furthermore, using an SLR approach helps to reclassify the issues that have been discussed related to the relationship between religiosity and life satisfaction.

Literature review Defining religiosity: An overview
The word 'religiosity' is interpreted in a variety of ways, and its meaning is interdisciplinary. It is not surprising that Gill et al. (2010) recognised that religiosity is a difficult term to define, which has resulted in numerous definitions and models of meanings for the word. This shows that the topic of religiosity cannot be studied solely to identify one aspect of its meaning (Gill et al. 2010). Villani et al. (2019) recognised the complexities of religiosity, prompting her to propose 13 items to comprehend its meaning according to the constructs of commitments, in-depth exploration and reconsideration of commitments. Gill et al. (2010) presented 13 items as the dimensions of religiosity, which generally refer to identity commitments, including a specific religious worldview. Holdcroft (2006) agreed that religiosity is a complex concept to define, at least for two reasons: (1) the uncertainty of the meaning of the root word 'religiosity', particularly in English, and (2) the approach to religiosity, which is multi-and even interdisciplinary due to the significant interests of scholars in studying religiosity across academic fields. These two factors also become the markers for why the dimensions of religiosity differ. Because there are various definitions for religiosity, there has been extensive studies on this subject.
Religiosity is a psychological phenomenon. Hence, it cannot be understood solely by identifying one dimension. It is not surprising that social and psychological scholars offer a variety of scales and items for assessing religiosity (Hill & Hood 1999). In this context, Abdel-Khalek and Lester (2017) defined religiosity as: [A] particular institutionalized or personal system of beliefs, values, and practices relating to the divine -a level of reality or power that is regarded as the source or ultimate transcending yet immanent in the realm of human experience. (pp. 12-13) Abdel-Khalek and Lester (2017) emphasised that religiosity refers to a system of personal beliefs, values and various religious practices. People require a belief system as a reference for a better life. This results from the transcendence process or the formal and informal institutionalisation of religious doctrine. It necessitates a strong understanding of experience, mental aspects and individual appreciation of the belief system that is embraced and firmly believed. This type of transcendence process becomes a psychological phenomenon. In addition, Iddagoda and Opatha (2017) identified that religiosity has dimensions such as orientation, behavioural set and lifestyle that are considered important by every community and accepted socially or personally. Thus, the dimensions of orientation, behavioural set and lifestyle are identified as the components of religiosity.
A set of brief information on various perspectives toward religiosity is shown in Table 1. Such studies provide a brief information on a variety of perspectives on religiosity. Joshanloo (2021) assessed religiosity using three questions: (1) 'Regardless of whether you belong to a specific religion, how religious would you say you are?'; (2) 'Aside from special occasions like weddings and funerals, how frequently do you attend religious services nowadays?'; (3) 'Aside from religious services, how often, if at all, do you pray?' These three questions address the dimensions of 'level of religiosity', 'frequency of participation in religious services', and 'frequency of prayer performed'. Joshanloo's (2021) dimensions are used to comprehend the impact of religiosity on life satisfaction. However, religiosity in this study is positioned as a variable that modifies and positively affects 'life satisfaction'. It indicates that religiosity can dynamically mediate between the variables 'positive effect of emotion' and 'life satisfaction'.
Ten Kate, De Koster and Van der Waal (2017) differed from Joshanloo (2021) in that they attempted to identify the direct effect of religiosity on life satisfaction, even with different dimensions of religiosity. They defined religiosity in two dimensions before examining its impact on life satisfaction. The first dimension is religious beliefs. A spiritual person's character is to adhere to religious beliefs, which can become the foundation for interpreting the empirical world and how individuals act and behave correctly in their lives. The second dimension is private religious practices. Theoretically, religious practice in private settings is a dimension of religiosity that can play a role. In accordance with this, Zotti, Speziale and Barra (2016) performed the same steps and studies on the effects of religiosity on life satisfaction. They discovered that there is empirical evidence that an individual's level of religiosity directly influences life satisfaction. These different variables (i.e. religious attendance and religious beliefs) associated with religiosity confirm one thing: the heterogeneity of religiosity dimensions used in one study is highly dependent and determinant with the endogenous variable (i.e. a dependent variable) that will identify the influence of religiosity on it. The relationship between religiosity and life satisfaction must be understood in this context.

The meaning of religiosity in cross-religions: A brief review
Religiosity in several studies is assessed as the influence of religion (Mohd Dali et al. 2019). This confirms an assumption that religiosity is highly dependent on the underlying religion. Thus, religiosity among Islam, Christianity, Buddhism, and Hinduism tend to be different because of the differences in the doctrines and beliefs in those religions. In Islam, Manurung (2014) identified that religiosity refers to consistent reflection and appreciation of Islamic values (Manurung 2014). In addition, religiosity in Islam refers to the fundamental awareness that human life today is only an instrument to achieve happiness in the hereafter, so that Muslims must perform good deeds (Anita, Kartowagiran & Ayub 2019). Thus, Islamic religiosity refers to 'the extent of the strength of faith, the belief of a Muslim in which the dogma is practiced daily' (Ajuna 2021).
Meanwhile, religiosity in the Christian tradition refers to the theological awareness based on the Trinitarian structure. This awareness encourages the belief that God is the creator of the universe. This faith must be practised and reflected in the daily behaviour of Christians (Hons 2010). Köllner (2020) identifies that religiosity in the Christian tradition refers to 'practical theology that manifests in the worship of the saints and daily prayer in living life' (Köllner 2020). The meaning of religiosity in two religions, namely, Islam and Christianity, shows the existence of theological awareness and is manifested in the daily behaviours of Muslims and Christians. Thus, a strong faith in God (i.e. Allah and Jesus) is reflected in various aspects of their life.
Meanwhile, religiosity in Buddhism has been identified by Verma (2020), as having several dimensions -from the theological realm to the appreciation of the values of Buddhism in everyday life. The Buddhist values are fully described in the Eight-Fold Path and the Lotus Sutra. It is just that religiosity in Buddhism is practiced differently among Buddhist schools. There are at least three schools of Buddhism, and they influence the meaning of religiosity practised by Buddhists. They are Theravada, Mahayana and Vajrayana (Verma 2020). In the Theravada school, it is recommended to heed the advice of sages, remember that advice and evaluate individual experiences and practices. The Theravada path begins with study, is followed by training and culminates in the attainment of Nirvana (Gombrich 1988).
In contrast to the Mahayana school, which emphasises the triumph of the Bodhisattva by opening the way to Buddhahood, the Vajrayana school believes that self-nature (human nature) is Buddha nature (the essence of the seed of Buddhahood). To attain Bodhisattvas, Buddhists need a qualified teacher whom the leaders of the four schools recognise: Nyingmapa, Sakyapa, Kagyudpa, and Gelugpa. In addition, qualified instructors teach total surrender of body, speech and mind and advise to take refuge in the Buddha, Dharma and Sangha (Gombrich 1988;Verma 2020). Buddhists can show high religiosity in everyday life with such beliefs and doctrines.
Religiosity in the Hinduism tradition has been identified by Baral (2020). He successfully found that religiosity in Hinduism has an intrinsic and extrinsic character. In this context, there are at least four kinds of Hindu religiosity: (1) ritualism: refers to Vedic-Brahmanistic ritualism, which is domestic and requires sacrifice, but does not include some forms of Tantrism; (2) spiritualism: intellectual piety, aimed at seeking freedom (moksa) for the individual, usually with the guidance of a teacher. This is characteristic of Advaita Vedanta, Saiva Kashmir, Saiwa Siddhanta, Neo-Vedanta, Esoteric Guruism and some kinds of Tantrism; (3) devotionalism: is the worship of God, as emphasised in the Bhakti and Krishna traditions and (4) heroism: a form of polytheistic religiosity stemming from militaristic traditions, such as Ramaism and parts of political Hinduism. It is also called wirya-marga (Baral 2020;Ramachandran 2018). The previous descriptions related to religiosity in Islam, Christianity, Buddhism, and Hinduism show different features of religiosity. This is due to the various scriptures and doctrines that form the foundation of religiosity in every religion. Maddux (2018) defines life satisfaction simply as a feeling of happiness and becoming satisfied with life. There are two keywords from the meaning proposed by Maddux (2018), namely, happiness and well-being. Individuals who are considered satisfied with life feel happiness and a sense of well-being. In this case, Toker (2012) understands life satisfaction as 'the degree to which a person positively evaluates the overall quality of the life as-a-whole'. This confirms that life satisfaction is subjective and personal, whereas individual satisfaction with life differs. Therefore, a universal standard of life satisfaction is needed (Lambert et al. 2009). In this context, Brown and Duan (2007) proposed predictors of life satisfaction, including individuals' demographics, psychological characteristics and life experiences. The proposal offered by Brown and Duan (2007) is not the only indicator that can predict and measure individual satisfaction with life. Nair and Gaither (1999) identified that marital status, social support and opportunities to socialise with the environment are closely related to life satisfaction. In addition, indicators such as health, leisure, family, work, financial situation, social relationships and self-worth were proposed as other indicators related to life satisfaction on a scale that is more often referred to by social scholars (Milovanska-Farrington & Farrington 2021). Na-Nan and Wongwiwatthananukit (2020) suggested several indicators that are rarely considered by other social scholars, related to life satisfaction. According to them, there are at least five important indicators related to life satisfaction, namely, (1) enthusiasm to do activities and attention to one's own living conditions; (2) resolution and fortitude as the acceptance of life values; tolerance of problems encountered in life and perception to problems as experience and learning resources; (3) compatibility between the desired and achieved goals as an indicator of success in life; (4) self-concept refers to satisfaction with one's health, and contributing meaningfully to society; (5) mood regulation as a means of knowing how to be happy, having a good attitude and positive emotions towards other people and the environment, and the ability to overcome sad events (Na-Nan & Wongwiwatthananukit 2020). Various indicators related to life satisfaction have been proposed. Although they differ from one scholar to another, two keywords can unite these differences and are agreed upon as the main indicators of life satisfaction: 'happy' and 'well-being'. Thus, individual life satisfaction can be described as the feeling of happiness possessed by individuals when they achieve the desired level of well-being.

Methodology
This study used two approaches to map the influence of religiosity on life satisfaction through 24 journal articles. Meta-analysis and SLR were the approaches utilised in this study. According to Wampold, Ahn and Kim (2000), metaanalysis is a statistical method for combining different results from a series of studies with similar issues and research questions. When other forms cannot answer one or more studies, this method can test hypotheses powerfully, and it can even eliminate ambiguity from narrative studies of a collection of literature studies. Through (Wampold et al. 2000) interpretation, it can be understood that the metaanalysis approach used in this study is useful for quantitatively synthesising research results from several countries concerning the influence and relationship of religiosity and life satisfaction. An SLR was also used as a method to map the issues and developments of the study model concerning the influence of religiosity on life satisfaction. According to Fisch and Block (2018), an SLR is primarily concerned with mapping emerging concepts related to a research issue. As such, the SLR approach was used in this study to map the ideas proposed by scholars in their publications about the effect of religiosity on life satisfaction. Tikito, El Arass and Souissi (2019) asserted that to conduct a meta-analysis, four aspects must be considered: information source, technology, method and impact. These aspects must be considered because they serve as the foundations for producing a quantitative analysis of the existing literature through meta-analysis. According to Israel and Richter (2011), because meta-analysis is a statistical technique used to combine several published studies, the data collected must be in the form of literature, that is, journal articles, working papers and research reports that can be accessed openly online. Referring to the model used by Tikito et al. (2019) and Israel and Richter (2011), the study applies a data collection model with two approaches, namely: meta-analysis and SLR. The criteria for the article selection process for meta-analysis included (1) data on the number of samples (N), R Square values and the countries where the studies were conducted;

Data collections
(2) descriptive statistical information in the form of the mean value of each variable and (3) full articles published in journals. Twenty-one articles were chosen based on these three criteria to be analysed using a meta-analysis approach. Following the meta-analysis, data were collected for conducting SLR to map issues and study directions related to the influence of religiosity on life satisfaction.
According to Okoli (2015), the SLR approach identifies specific literature relevant to the study's objectives. Following the establishment of the article selection criteria, the researchers synthesised the methodology employed in each article and the theoretical arguments advanced by previous researchers. This was done because SLR, as a method, essentially assists and allows researchers to develop theories through a review of previously published literature (Nomran & Haron 2019;Okoli 2015). In this regard, this study chose 21 articles based on the following criteria: (1) the article had a full version and was published in a journal; (2) the selected article was a study that investigated the influence of the variables of religiosity on life satisfaction and (3) the article could be accessed primarily through the databases of Google Scholar and Science Direct. It is hoped that using these procedures and criteria, the issues of religiosity and life satisfaction can be mapped out from the published literature.

Analytical procedure
This study employed two data analysis models: data analysis using a meta-analysis approach and data analysis using SLR. This study employed a comprehensive meta-analysis to examine the effect of religiosity on life satisfaction (Al-Wasy 2020). Stata 16.0 software was used to aid in the analysis. Data such as correlation coefficients and sample sizes were used to calculate the effect sizes of religiosity on life satisfaction (Leong et al. 2021). Moreover, the data analysis using the SLR approach was performed through a consistent and critical analysis of the characteristics and issues contained in the literature related to religiosity and life satisfaction. This procedure was used to map the variables and indicators used in the existing literature on the influence of religiosity on life satisfaction (Ahmad & Omar 2016). In the end, the mapping process served as the foundation for determining the direction of studies on religiosity and life satisfaction.

Religiosity's effect on life satisfaction based on the meta-analysis approach
This study employed a meta-analysis approach to 21 articles concerning the effect or influence of religion on life satisfaction. Hence, these criteria became the foundations for omitting the articles that did not meet the standards and selecting those conforming to the requirements for executing meta-analysis. These articles were found by searching the Google Scholar database. The journals in which the articles were published were then determined (Israel & Richter 2011). Eighty-five percent or 17 articles examined were classified according to the first selection criterion. The articles had been published in reputable international journals indexed by Scopus. The remaining 15% of the articles were published in journals that Scopus did not index.
In the other aspect, such as the number of samples, the articles chosen were fairly diverse. The sample sizes were small, but they met the requirements for analysis. For others, the sample sizes were quite large. Samples came from a variety of countries, not just one. Three studies used very large examples of data, all of which used data from the World Values Survey. Moreover, the countries where the researchers collected the samples were relatively diverse, i.e., Indonesia, Iran, Korea, the US, Peru, Greece, and Australia. Asia, the Americas and Europe were all represented. This confirmed that the studies were carried out in various locations, with relatively high sample heterogeneity. Because the samples were drawn from different countries, it could be concluded that the samples were also heterogeneous in terms of demographics and not homogeneous. The heterogeneity of such samples is critical in quantitative studies to draw robust conclusions (Tikito et al. 2019). The samples used by 21 articles in the selected studies could be considered a very high variation of samples. Therefore, they already met the representative sample criteria (Creswell 2013). It meant that the samples could represent the population and different studies on the same issue. Table 2 summarises the four aspects of the articles investigated in the meta-analysis. These aspects include authors and years, locations, method and the number of samples used. Based on the information displayed, it is clear that the 21 studies chosen were diverse and heterogeneous. The heterogeneity was identifiable from the varieties of study locations in various countries. Similarly, the methodologies used by the 21 studies varied although the linear regression approach was dominant in general. Another factor that varied greatly among these studies was the number of samples used. Faheem et al. (2019) conducted a study with a minimum sample size of 80 samples. The largest sample size was obtained in a survey conducted by Plouffe and Tremblay (2017) that included 85 072 samples. Thus, although there were only 21 articles chosen for this study, the articles met the criteria for study representation. However, the papers had represented the existing studies (Tikito et al. 2019) by the degrees of site heterogeneity, method and sample number. Considering the information in Table 2, incorporating the 21 studies into the metaanalysis was feasible and conceivable. Table 3 provides several statistical aspects of the existing studies related to religiosity and life satisfaction, which could be interpreted differently. Firstly, this study had a relatively small number of articles selected, but these articles were sufficient and met the meta-analysis standards. The preceding was indicated by the significant value of the homogeneity test (0.0000). Thus, because the Q value was statistically significant, all included studies could be synthesised (Kulinskaya, Dollinger & Bjørkestøl 2011). Secondly, the heterogeneity value, when using the 'random effect' method to combine the effect quantity, was significant (p < 0.00). This demonstrated heterogeneity, so the results of meta-regression on religiosity could explain the heterogeneity among effect sizes (Kulinskaya et al. 2011). Thirdly, Figure 1 indicates that the influence of the religiosity variable on life satisfaction was significant in various study settings. This was demonstrated by the effect size overall statistical value of 2.85 (effect size with 95% CI). This confirmed that the influence of religiosity on human life satisfaction was very contributive and significant (Lim & Putnam 2010;Ten Kate et al. 2017). The meta-analysis approach used in the studies on the effect of religiosity on life satisfaction confirmed a theoretical belief that the religiosity variable is a powerful variable that explains and even influences human life satisfaction in various aspects. This is undoubtedly an impetus for academics to continue researching variations in the  The statement 'by the large majority of people worldwide' is not acceptable because there can be a religion that a small number of people believe in. They also have religiosity.

King and Williamson
2005 The strength of one's connection to or conviction for their religion.
-'One's connection' is like a bond to the religion.
-'Conviction for their religion' means belief in their religion.

Adeyemo and Adeleye
2008 Religiosity includes having belief in and reverence for God or a deity and participating in activities in that faith, such as attending service/ worshiping regularly and participating in other social activities with one's religious community.
-'God or a deity' is not acceptable in some cases.   Lewis et al. 1996). In terms of religiosity, two sources contributed to an individual level of religiosity: theological awareness and appreciation of religious teachings or dogmas (El-Menouar 2014). The existing studies gave rise to three conceptual types in formulating the construct of religiosity during its development. Some studies interpreted religiosity only in terms of theological awareness, so the indicators chosen included all forms of beliefs in transcendental things, such as God, hell, and heaven (Clark & Lelkes 2011;Kongarchapatara et al. 2014;Park et al. 2012). Other scholars interpreted religiosity based on the consistency of religious rituals, such as religious service attendance, membership in religious organisations and prayers (Ayten & Korkmaz 2019;Kıraç 2016

Discussion
Religiosity is a complicated concept (Holdcroft 2006;Rulindo 2002). Therefore, it encourages various scholars to comprehend and formulate its vision broadly and across many disciplines. The availability of various dimensions (i.e. the dimensions of religiosity and life satisfaction) is the result of studies on religiosity and life satisfaction, as shown in Table 4. Meanwhile, these dimensions (i.e. theological awareness, appreciation and integration of theology and rituals) significantly affect life satisfaction (Cohen et al. 2005), including material and psychological life satisfaction. Although most studies identified a linear relationship between religiosity and life satisfaction, one viewpoint that can be proposed here is that religiosity does not affect human life satisfaction as a single factor (this must be in conjunction with other factors). However, in some cases, religiosity, in conjunction with other factors, affects the life satisfaction of religious adherents (Chesser et al. 2018), including Muslims, Christians, Hindus and Buddhists.  (Guiso, Sapienza & Zingales 2003). The outcomes of the operation of faith eventually form different rationality in humans. Weber (1992) demonstrated how the spirit of religion (i.e. protestant ethics) could shape positive economic views and behaviour, thereby encouraging the development of the nature of capitalism. Moreover, the study delivered and succeeded in introducing the concept of rationality (Weber 1992), which is important in understanding human behaviour and useful in determining how humans define satisfaction and happiness.  Kalberg (1990) carefully identified the term rationality, which frequently appeared in Max Weber's studies. This rationality includes logical reasoning as well as teleological consistency. The rationality based on calculating the profit and loss is referred to as instrumental rationality. Subsequently, teleological rationality is a religious reasoning-based rationality (Kalberg 1980). In terms of life satisfaction, religiosity can then be interpreted as a product of religious worldviews that religious adherents live by Kalberg (1990). This means that human life satisfaction results from internalisation in light of spiritual understanding, that is, by the way religion teaches humans to be grateful for what they have. In this context, Max Weber introduced religion as 'religion loci': a concept held by Weber that religion provides various qualifications and definitions of life that humans can accept (Kalberg 1990). As a belief system, religion influences (quantitatively) and fundamentally shapes (qualitatively) human behaviour and determines how humans interpret happiness and life satisfaction. This notion supports the assumption that religiosity has a significant relationship to life satisfaction in varied conditions and fields of work.

Conclusion
The present study uses meta-analysis and SLR approaches to reaffirm that religiosity significantly influences human life satisfaction in various situations and conditions. Metaanalysis has successfully mapped that the relationship formed between religiosity and life satisfaction is linear. However, in some studies, religiosity is a moderating variable, strengthening non-religious factors on life satisfaction. This does not diminish the fact that religiosity is a factor that influences human life satisfaction. This conclusion becomes more theoretically robust when various dimensions of religiosity and life satisfaction are tested quantitatively and they are statistically significant in multiple studies.
Furthermore, it seems necessary to recognise that this study merely attempts to synthesise the existing studies on religiosity and life satisfaction. Of course, such a strategy has drawbacks and limitations. This study does not identify how religiosity determines and dominantly affects humans in defining life satisfaction. Thus, this aspect can be studied more intensively in the future, specifically through the emic perspective. Through this emic perspective, at least it can explain the quality of life satisfaction and its relationship with religiosity using the point of view of a particular society. In this regard, studies on the preceding issue will undoubtedly become important and theoretically meaningful.