Halal service quality: systematic review, conceptual model and future research

Services play a critical role in the Islamic economy. Key halal service industries such as Islamic finance, Muslim-friendly travel, and media and recreation continue to grow between 5.5% and 9% annually and contribute to a global halal economy worth US$2.29tn in 2022 (DinarStandard, 2023). Across these halal industries, Muslim consumers continue to evaluate how these services perform (Noor, 2022). One key method of assessment is the consumers’ perceptions of the service, also known as service quality.

Service quality is the perceived excellence and superiority of the service and a type of attitude formed by customers (Zeithaml, 1988). Since the early studies of service quality (Grönroos, 1984; Parasuraman et al., 1985), service quality research has grown substantially to represent a mature research stream (Ladhari, 2009, 2010). One of the key priorities in service quality research involves the measurement of service quality and what constitutes the dimensions of service quality (Zeithaml et al., 1990). A clear understanding of the factors that matter to consumers in their perception of service quality has clear implications for better design and benchmarking of service performances. To this, research has established that service quality is multidimensional, and the dimensions can be affected by the service environment and the unique service agents consumers interact with (Rust and Oliver, 1994).

Indeed, the way consumers experience service has changed, from interacting with traditional human service agents to today’s increasingly emerging technologies, including artificial intelligence (AI) (Noble et al., 2022). Accordingly, scales used to measure service quality have evolved. The seminal SERVQUAL scale (Parasuraman et al., 1991; Parasuraman et al., 1988) addressed services provisioned primarily by human service providers and contained the dimensions of reliability, assurance, tangibles, empathy and responsiveness. Since its development, other scales have been introduced to measure service quality in other service environments more accurately. This includes WebQual for website services (Loiacono et al., 2007), SSTQUAL for self-service technologies (Lin and Hsieh, 2011), M-S-QUAL for mobile services (Huang et al., 2015) and AISAQUAL for services performed by AI (Noor et al., 2022). There have also been scales designed for specific industries, including DINESERV for restaurants (Stevens et al., 1995). Raajpoot (2004) developed the PAKSERV scale and its service quality dimensions of tangibility, reliability, assurance, sincerity, personalization and formality for more Asian cultures. Overall, while measure items and dimensions related to reliability appear frequently in service quality scales (Noor et al., 2021) and are a critical factor for service quality performance (Zeithaml et al., 1990), different scales contain unique combinations of service dimensions relevant to consumers in the particular service environment.

With the importance of service quality and its established effects on the outcomes of perceived value, customer satisfaction and loyalty (Cronin et al., 2000), researchers have comprehensively examined the literature concerning service quality in the form of systematic literature reviews (SLRs) to better understand the state of knowledge of this key research area as well as the research trends and opportunities (Ladhari, 2009, 2010; Seth et al., 2005). SLRs as a research methodology allow for a state-of-the-art understanding of a knowledge domain as well as the discovery of research gaps and new research opportunities (Lim et al., 2022; Paul et al., 2021). In the Islamic marketing literature, SLR contributions have deepened the understanding of diverse halal sectors, including the service sectors of Islamic finance (Alshater et al., 2022) and Muslim-friendly travel (Abdul Shukor and Kattiyapornpong, 2024). SLRs have also contributed to a richer understanding of the applicability of seminal models in the halal context, including consumer behavior (Maminirina Fenitra et al., 2024) and technology acceptance (Noor, 2024).

Despite the significance of service quality in both the literature and the halal economy, there has yet to be a comprehensive review of service quality research in halal industries in the form of SLRs. Studies on halal service quality research in halal industries have made significant strides in both services marketing and Islamic marketing literature. For instance, researchers have investigated the applicability of seminal models such as SERVQUAL (Kamarudin and Kassim, 2021) and PAKSERV (Kashif et al., 2015) in halal industries. Augmentations to seminal models have resulted in novel service quality models for halal markets, including CARTER (Dandis et al., 2021) and CREATOR (Khan et al., 2023). The CARTER model features the additional dimension of compliance with Islamic law, with five-item measures such as “The bank runs on Islamic law and principles,” while the CREATOR model further includes the dimension of operational effectiveness. Other studies considered multiple service quality models (Ratnawati et al., 2021) as well as proposed entirely new service quality models with dimensions more peculiar to the Islamic faith, such as Islamic values and Shariah compliance (Asnawi et al., 2020). While the findings from these studies are important, the insights are currently fragmented; there is a lack of a holistic and comprehensive understanding of the current state of research on service quality in halal industries, which can be achieved through an SLR.

In line with the above research gaps, this article seeks to offer a better knowledge of service quality in halal industries through an SLR and aims to answer the following research questions:

This research aims to fill a critical gap by providing an updated and comprehensive understanding of the service quality model in the context of halal industries. Given the rapidly changing service environment, including the rise of AI in service encounters (Huang and Rust, 2020; Wirtz et al., 2018), a comprehensive view of the overall service quality landscape across halal sectors will provide practitioners and policymakers with critical insights to adjust, propose, and develop better service environments for customers. These insights can result in better design, benchmarking, and quality control of halal services. For researchers, this SLR will create more opportunities for research by analyzing what is currently known about halal service quality research and what should be done to advance the knowledge of halal service quality.

The following sections proceed to describe the methods used in conducting the SLR, followed by the results of the SLR. Subsequently, the paper discusses the findings and conclusions of the study before presenting a research agenda to advance the study of service quality in halal industries.

An SLR guided by the Scientific Procedures and Rationales for Systematic Literature Reviews (SPAR-4-SLR) (Paul et al., 2021) was used to address the research objectives. SPAR-4-SLR was chosen as the systematic review methodology compared to previous protocols such as the preferred reporting items for systematic review and meta-analysis (PRISMA) as SPAR-4-SLR offers greater clarity and transparency in the assembling, arranging, and assessing stages of the systematic literature review process (Paul et al., 2021). The key stages of the review using SPAR-4-SLR are summarized in Figure 1.

In the assembling stage, journal articles were searched in the Web of Science (WoS) database. WoS has been used in past SPAR-4-SLR studies in services (Blommerde, 2023) and Islamic marketing (Liew and Karia, 2024). In addition, WoS was chosen over Scopus in this study as WoS is a stringent quality journal database and yielded a more manageable number of quality articles for this SLR as compared to Scopus (Paul et al., 2021). In terms of the search period, as the number of articles in the collection was manageable, the start date was left open (unspecified) and the end date was 2024, which was the data collection period in this research. Keywords were selected based on the scope of the review and included the following terms: “halal,” “Muslim*,” “Islam*” AND “service quality.” The keyword search was done on the abstract of journal articles. Upon further filtering for only English language articles, a total of 122 articles were retained in the assembling stage.

In the arranging stage, content from the articles was extracted using the theories, contexts, characteristics and methods (TCCM) framework (Paul and Rosado-Serrano, 2019). SLR frameworks such as TCCM have been advocated in the literature because of their robustness and benefits (Paul et al., 2021) and have been used in service research together with the SPAR-4-SLR protocol (Blommerde, 2023). The use of TCCM would allow the SLR to capture the characteristics related to the modifications of service quality models. In the next purification phase, no duplicates were found. Only empirical articles that featured service quality as an underpinning theory and were written in the context of halal industries were included. Hence, articles in which service quality had been discussed but not applied to a service quality research model (Alenizi, 2023) and articles in which the nature of the industry studied was not clearly focused on a specific halal sector, for instance, a general health-care sector (Zarei et al., 2014) as opposed to halal pharma, were excluded. Accordingly, a total of 44 articles were excluded and the remaining 78 were included for assessment.

The final assessing stage involved evaluating and reporting the articles in evaluation with the accompanying use of figures and tables. The bibliometric characteristics will be discussed, followed by a content analysis based on the categories organized using the TCCM framework-based review. Based on the current research status of service quality in halal industries and the gaps identified, a research agenda is proposed to conclude this paper. The following sections elaborate on the results of the SLR analysis.

This section focuses on the descriptive statistics related to the journal publications and year of publications of the 78 articles analyzed in this paper.

Table 1 depicts the 78 journal publications based on the articles considered in this study. There are a total of 36 journal titles featured in this study. The Journal of Islamic Marketing has the greatest number of publications, with 22 out of the 78 articles or 28.21%. Seven journals, namely, the Journal of Islamic Marketing, Journal of Islamic Accounting and Business Research, Cogent Business and Management, International Journal of Bank Marketing, Journal of Asian Finance Economics and Business, International Journal of Business and Society and African Journal of Business Management, have published more than one article in the area under review. Four out of the 36 journal publications in Table 1, namely, the Journal of Islamic Marketing, Journal of Islamic Accounting and Business Research and Al-Shajarah and Turkish Journal of Islamic Economics-Tujise, are focused on halal or Islamic industries. Journal publications also span several industries, including finance, hospitality, technology and education. These results show both the focus of halal service quality research in the context of halal industries as well as how studies in halal service quality can be relevant for research outlets with broader industry contexts.

Figure 2 displays the publication trends of the articles considered in this study. Overall, since the first study of bank service quality in 2010 by Ahmad et al. (2010), research in this area has steadily increased, with a spike in 2019 and a total of eight articles published in that year. The peak of publication numbers in this review happened in 2020 with a total of 20 articles. Publications on service quality in halal industries remained above 10 articles till 2023. The four articles published in 2024 by Suhartanto et al. (2024), Kayumov et al. (2024), Gayatri et al. (2024) and Ahmad et al. (2024) represent a positive outlook of service quality research in halal industries with a rich set of papers spanning different industries (halal food, halal pharma, Islamic finance), countries (Indonesia, South Korea, Pakistan), service agent types (mobile, human) and research methods (quantitative surveys, qualitative interviews, mixed-methods). Overall, the general decline in halal service quality research since 2020 is concerning as the service environment continues to evolve, particularly with new emerging technologies, and such changes require a continued understanding of how customer perceptions of halal service performance may change.

The following section analyzes the 78 articles in the review using the TCCM framework as advocated by Paul et al. (2021) and used in SLRs related to services (Blommerde, 2023; De Keyser and Kunz, 2022) as well as those peculiar to halal markets (Islam et al., 2023; Noor, 2024).

In this paper, theories refer to the service quality model that was studied in the paper under review. As shown in Table 2, a total of 50 articles or 64.10% featured bank service quality as the service quality model in their studies. Only five articles were focused on the service quality of technological service applications, namely, e-service quality (Ahmed et al., 2021; Baber, 2019; Syah and Olivia, 2022; Tabash et al., 2019) and mobile service quality (Suhartanto et al., 2024). Once again, this is a cause for concern, as there is a lack of service quality research on how halal service quality may be affected by the dramatic changes in the service environment because of emerging technologies, including AI and the metaverse.

In this study, context refers to the country, halal industry, transaction type and main service agent as featured in the articles of this review.

Table 3 provides the list of countries in which this review was conducted. Of the 78 articles, 21, or 26.92%, were conducted in the Indonesian context, while 13, or 16.67%, were in the Malaysian context, followed by 11, or 14.10%, in the Pakistani context. These three countries are representative of the top 15 Islamic economies in 2022 (DinarStandard, 2023). Except for three studies done in Tanzania (Ismail, 2023; Tegambwage and Kasoga, 2022, 2023), two in South Korea (Kayumov et al., 2024; Shokhsanam and Ahn, 2021), and one in Thailand (Jeaheng et al., 2020), the majority of the identified countries in the list of studies under this review are Muslim countries in the Organization of Islamic Cooperation (OIC) (DinarStandard, 2023). As halal markets can also exist in non-Muslim countries, the lack of research and understanding of halal service quality in non-Muslim countries can be an obstacle to creating a successful global halal service brand.

In terms of the industry context, this paper adopts the categorizations based on the halal industry classifications from the State of the Global Islamic Economy (SGIE) report (DinarStandard, 2023). Islamic education, not present in the SGIE report, has been added to the paper by Asnawi and Nina Dwi (2020) focusing on the service quality dimensions of Islamic higher education.

Table 4 provides the list of halal industries in the articles reviewed. Out of the 78 articles, 54, or 69.23%, were focused on the impact of service quality in the Islamic finance industry. This is reflective of Islamic finance being the key sector driving the halal economy (DinarStandard, 2023). There were three articles related to the study of service quality in the halal pharma industry (Gayatri et al., 2024; Ratnawati and Kholis, 2019; Ratnawati et al., 2021), with one study in the sectors of Islamic education (Asnawi and Nina Dwi, 2020) and Modest fashion (Syah and Olivia, 2022), respectively. Three out of the five main sectors in Table 4, namely, Islamic finance, Muslim-friendly travel and Islamic education, are in service industries with a total of 82.05% of the articles in review. The emphasis on service quality research in these sectors supports the significance of halal service sectors (Noor, 2022). There is a representation of all key halal sectors in the review as featured in SGIE except for halal cosmetics and halal media and recreation. The lack of understanding of halal service quality can impede the growth of what are otherwise two promising industries in the halal economy (DinarStandard, 2023).

While the service quality model was originally developed to measure customer perceptions of service quality in business-to-consumer (B2C) settings, the literature has acknowledged the important role of internal service quality and how the service performance of business-to-business (B2B) transactions can affect overall organizational performance (Heskett et al., 1994). Accordingly, Table 5 illustrates the focus of service quality research on halal industries in B2C transactions, with only three out of the 78 articles or 3.85% discussing internal service quality in B2B settings. Two of these B2B studies were related to the halal food industry in the context of food logistics (Zailani et al., 2018) and contract manufacturing (Rahim et al., 2020), while the other studied the effects of quality of internal control systems on employee performance in Islamic banks (Jarah et al., 2023). The lack of halal service quality research in B2B transactions will represent another barrier to growing halal brands with strong business ties and partner relationships in the ecosystem.

As established in this paper, there have been various service quality models developed for various types of service agents. For the articles in review, as seen in Table 6, 70 out of 78 articles or 89.74% were concentrated on the service quality evaluations of mainly human service providers. Despite the significance and proliferation of technologies in services (Noble et al., 2022; Parasuraman, 2000; Wirtz et al., 2018), less than 10% of articles studied the element of online service quality in halal industries, with only one article specifically focusing on mobile service quality (Suhartanto et al., 2024). None of the articles explicitly looked at the service quality of self-service technologies (Lin and Hsieh, 2011) and emerging technologies, including AI (Noor et al., 2022), which represents a gap in the knowledge domain of how different service agents can affect halal service quality.

The characteristics section of this review will analyze the articles based on the service quality dimensions and the relationships between the key components of the service quality model and its variations across halal industries.

Service quality models are often captured as multidimensional scales (Brady and Cronin, 2001) with several key outcomes, including customer satisfaction, perceived value and loyalty (Cronin et al., 2000; Noor et al., 2022; Oh, 1999). Accordingly, this paper maps the various factors from the empirical relationships found in the articles in review according to the antecedents of service quality (ANT), service quality (SQ) dimensions that were indicated in the studies and found significant, outcomes to service quality in terms of customer satisfaction (SAT), perceived value (VAL) and loyalty (LOY) and moderators that affect the relationship between service quality and its outcomes (MOD). The relationship between service quality and loyalty was mapped both in terms of direct and indirect relationships as prevalent in the literature. Table 7 details the service quality dimensions and relationships found. For the relationships between service quality and its outcomes, “Yes” indicates a positive relationship, “No” indicates the relationship was tested but not found to be significant, and blank indicates the relationship was not measured in the study. Table 8 shows the accompanying frequency of relationships between service quality and satisfaction, perceived value and loyalty.

Out of the 78 articles in review, 52 papers or 66.67% featured multidimensional service quality models, while the remaining studies used item measures only without defined dimensions as factors in their service quality scales. Of these, 22 studies featured the five dimensions of SERVQUAL as part of their service quality models and found these dimensions to be significant in the halal industry. Nine studies featured all six dimensions of CARTER and found them significant as well. These findings support the service quality literature in which changes to the service environment can affect the composition of the service quality dimensions (Zeithaml et al., 1990).

Only 5 out of the 78 studies or 6.41% found antecedents with significant relationships to service quality. Out of the 78 studies, 27, or 34.62%, found significant relationships between service quality and outcome variables other than satisfaction, perceived value and loyalty. Out of the 78 studies, 10, or 12.82%, found moderators that significantly affected service quality with outcome variables. Of these, religiosity was found to be an antecedent in the Islamic finance industry (Abror et al., 2023a) and a moderator in the Islamic finance (Tegambwage and Kasoga, 2023) and Muslim-friendly travel sectors (Ezeh et al., 2022).

In terms of the relationships between service quality and the key outcomes of satisfaction, perceived value and loyalty, satisfaction was most tested with 44 articles or 56.41%, finding this relationship significant. The indirect effects between service quality and loyalty were the next most tested relationship, with all instances of this relationship being significant when tested. Out of the 20 times in which the direct effect between service quality and loyalty was tested, 20% or 4 studies showed the relationship is insignificant. Finally, only 7 articles or 8.97% studied the effects of service quality on perceived value. This represents a lack of understanding in the field of how service quality can contribute to consumers’ perceptions of the value of halal service firms.

While Table 7 provides a granular understanding of the dimensions of halal service quality, an overall understanding of the common themes of drivers and consequences of halal service quality across all industries will also provide broad and rich insights. The above review has uncovered the overall antecedents and outcomes of halal service quality. Similar to Hollebeek et al. (2024), this study synthesizes the antecedents and outcomes across all industries to produce the conceptual model in Figure 3.

Figure 3 highlights the importance of culture, technology, and faith-related factors in driving halal service quality. These faith-related factors are unique to the nomological network of halal service quality and comprise Islamic shariah compliance measures such as “[…] runs on the principles of Islamic Shariah” and “[…] offers Islamic products and services only” (Ahmed et al., 2022), religiosity measures such as “Islam helps me to have a better life” and “I perform all my prayers” (Abror et al., 2023a), and Islamic place attributes with measures including “Availability of Halal food” and “Banning of alcoholic drinks at public places” (Abror et al., 2023b). As for the outcomes of halal service quality, these consequences can be categorized as mainly consumer- or firm-related. These findings show how halal service quality can be similar to traditional service quality in terms of capturing common outcomes (e.g. satisfaction, perceived value, loyalty) but also unique (e.g. faith-related factors).

Table 9 shows the dominance of quantitative surveys as a research methodology in articles that investigate service quality in halal industries, with 89.74%. Five articles used a mixed-method approach (Ahmad et al., 2024; Farrag et al., 2022; Ltifi et al., 2016; Rahim et al., 2020; Zailani et al., 2018), while two articles analyzed databases of Tripadvisor.com (Lari et al., 2019) and booking.com reviews (Arasli et al., 2023). One article used qualitative interviews (Gayatri et al., 2024). The lack of exploratory methods indicates that researchers have not focused on exploring new concepts and theories of service quality in the context of halal service firms interacting with new service environments.

The service environment continues to evolve and affect all industries within it including services primarily catered to the needs of a growing global Muslim population. Hence, the study of service quality remains relevant and critical with more halal service sectors driving the global Islamic economy. This paper has explored the research area of service quality and the application of service quality models in halal industries through an SLR. The review paints a picture of the strong support the Islamic finance sector has in service quality research. While recent research papers have continued to look at service quality in other halal industries, the downward publication trend in this area over the last half-decade is a cause for concern amidst the continued push for halal service industries to grow and the need to navigate the changing service environment effectively. Hence, this review is a rallying call for more halal service quality research.

This study provides several important implications for practitioners and policymakers. First, service managers will be able to use the insights from this SLR to gain a deep appreciation of the various factors contributing to service quality and the impact of service quality across various halal industries. The breakdown of service quality factors by each halal industry in Table 7 allows for further strategic perspectives and planning based on the relevant service dimensions that matter to halal markets within each industry. For instance, halal food quality managers need to pay particular attention to food quality and safety for diners, while halal hospitality and tourism managers require extra care in providing quality facilities to guests. Second, the granular breakdown in Table 7 allows for a comparison and benchmarking of service quality measures both within a halal service industry and between industries for further service innovation and for service brands operating in multiple halal industries. Third, having a clear view of the antecedents and outcomes of halal service quality allows managers to focus their resources on creating better service performances as well as effectively build their case on the importance of service quality for their halal markets in building both consumer-related and firm-related equity. Fourth, the consolidated conceptual model in Figure 3, which synthesizes the antecedents and outcomes of halal service quality, allows for more consolidated governance and regulation of service quality standards in halal industries. Fifth, the conceptual model highlights the importance of having experts who can advise halal service firms in the areas of culture, technology, and faith.

As for research contributions, this study adds value to the literature in several ways. First, this SLR provides researchers with a clearer understanding of the state of research on service quality in halal industries and the significance of various factors within each industry. In support of the service quality literature, theoretically, it is clear that different halal service environments can give rise to different service quality dimensions. Traditional outcomes of service quality can also remain relevant in the halal service context. This understanding is fundamental to encouraging growth in the knowledge domain of halal service quality. Second, both Table 7 and the conceptual model in Figure 3 offer value for multidisciplinary researchers to better investigate other important antecedents, dimensions, and outcomes of service quality that can also be unique to halal contexts. For instance, given the growing emphasis on environmental sustainability, more research is required to understand the important role of green consumers in driving halal service quality and how halal service quality can contribute to the well-being of consumers and the betterment of the environment. Third, this review has identified that while there is a healthy trend of service quality research in this field, research needs to expand to include more industries, target markets, and technologies. The lack of technology-related antecedents in halal service quality research is particularly concerning given how emerging technologies such as AI and the metaverse are disrupting the service landscape. Finally, insights from what has been done with regards to the theories, contexts, characteristics, and methods in research on halal service quality provide directions for 16 specific research questions to expand the knowledge domain of this field. These questions are detailed in the concluding Table 10.

Despite these contributions, this research contains several limitations. First, the studies in this SLR are based on the WoS database, which, while allowing for a manageable analysis with quality articles, limits the articles in review. Future studies can consider additional databases to deepen the research insights. Second, this study considered research in which the main focus was on the phenomenon of service quality in halal industries. A further study can be conducted for a holistic understanding of the state of service quality research of general industries targeting Muslim consumers.

Based on the research gaps discussed and other opportunities identified from this paper, the following research agenda is proposed in Table 10 to advance the understanding of service quality in halal industries.