The present study systematically reviews the relevant literature to trace the evolution of service quality gap models since the original Service Quality Gap Model and identify the main distinctions between them. The study thereby aims to enable a deeper understanding of how subsequent models have modified the original model to be more applicable to specific sectors and changing technology.
A systematic literature review strategy and conceptual review methodology were used to achieve the study’s purpose. Using the Web of Science (WOS) database as the main source, the study applied reference tracking, visual search and AI-based validation to make the review as comprehensive as possible. The 183 publications meeting the inclusion criteria were reviewed to identify modified service quality gap models, determine their differences from the original model, and then group them in terms of sector applicability and theoretical contribution.
Fourteen distinct service quality gap models were identified (for publications from 1987 to 2022). Parasuraman et al.’s (1985) model remains influential, despite repeated criticisms, with almost all (93%) of the 14 models still drawing from it. Most revisions have added new gaps and/or modified existing gaps so as to provide a more nuanced representation of current service environments. Accordingly, model complexity has tended to increase in terms of the number of gaps (between 3 and 14). In particular, employee perceptions and internal service quality have become more prominent in newer models, while technology-focused models have incorporated automated and digital service delivery as new challenges. Finally, regarding sector specificity, newer models have been most commonly adapted for technology, transportation and tourism.
Despite the comprehensive nature of this review, several limitations should be acknowledged. First, the search strategy, while methodical, was primarily focused on the WOS database, which may have resulted in the exclusion of relevant models published in sources not indexed in WOS. Although complementary methods such as reference tracking, visual search strategies and AI-based validation were employed to mitigate this limitation, it remains possible that some service quality gap models published in less accessible journals, conference proceedings or non-English literature were overlooked.
First, the review’s categorization of service quality gap models enables organizations to select and/or adapt a model that is most relevant to their sector-specific challenges and business requirements. These include tourism and hospitality-related models (e.g. Lewis, 1987; Tsang and Qu, 2000; Lee et al., 2016); models for sectors with rapidly advancing technology (e.g. Kang and Bradley, 2002; Zhang et al., 2022); transport-related sectors like airlines, logistics and maritime companies (e.g. Frost and Kumar, 2000; Chen and Chang, 2005; Kahnali and Esmaeili, 2015); and healthcare (e.g. Lovelock and Wirtz, 2004). Second, the findings suggest that, through strategic choices of measuring systems, organizations should capture the employees’ as well as the customers’ perspectives. However, given that these models are becoming more complex, organizations will need to offset comprehensive measurements against feasibility. Third, given the expansion of digital services, organizations will have to take technology into account while evaluating service quality. By identifying such gaps, organizations will be better able to predict changes in customer expectations and offer their employees more relevant, focused service quality training initiatives.
First, service quality models are intended to make consumer experiences standard across sectors and enable customer expectations to be managed successfully through honesty and transparency in communication. Second, newer models increasingly focus on internal service quality, which indicates an acknowledgement that customer satisfaction cannot be achieved without first ensuring employee satisfaction. Third, newer models increasingly incorporate technological developments, which indicates a recognition of the need for equitable technological access to prevent digital divides. Finally, acknowledging the need to increase consumer trust in those sectors that have previously provided poor service experiences, newer models incorporate accountability mechanisms. These aim to improve customer experience by empowering consumers while interacting with service providers.
This paper represents the first systematic effort to compile and analyze all revised service quality gap models developed over the past 4 decades. While prior research has critiqued individual models or introduced alternative frameworks, no study has comprehensively examined and consolidated the full range of modifications to the original model across a 40-year span. By categorizing and evaluating the models, particularly regarding their sector-specific applicability, the present study’s findings can provide a useful resource for those, whether researchers or practitioners, investigating how service quality measurement frameworks are evolving to address specific sectors and be applicable to current business environments.
