Perceived quality of products: a framework and attributes ranking method
In this paper, we aim to contribute to the product development approach by introducing the Perceived Quality Framework. This attribute-centric framework can serve as a platform for robust discourse around the theme of perceived quality that is not limited by the product type or production method. To achieve this, we performed data-collection studies over four years, examining ten global automotive companies from five different countries. We will then demonstrate a method to evaluate the perceived quality of a product (PQAIR). This study builds on the assumption that multi-sensory information related to a product, assessed with the help of attribute-centric framework and mixed methods is a promising approach for tackling a complexity of the perceived quality evaluation.
However, the PQF and PQAIR method are not limited to use in the automotive industry alone. The PQF focuses on the product attributes that communicate quality to the customer – i.e. perceived quality attributes. Perceived quality attributes can be defined as characteristics that convey functional and psychosocial benefits of a product to the customer (Steenkamp Citation1990 ). While we have collected, and structured information about perceived quality attributes applicable to the automotive industry, the same or a modified set of attributes can be used in various domains of product development for evaluation of perceived quality. Research in this area indicates the full spectrum of opportunities regarding the use of PQF and PQAIR method for consumer products. If a company wants to communicate quality aspects of the product, there is eventually a need to bring these characteristics into the measurable space of perceived quality attributes. There is evidence that insufficient methodological support causes the industry to employ intuitive rather than strategic or systematic communication practices (Liem, Abidin, and Warell Citation2009 ). In our previous work (Stylidis et al. Citation2014 ), we demonstrated how companies translate their core values into the perceived quality attributes and how customers perceive these core values. In practice, Original Equipment Manufacturers (OEMs) usually communicate their values to the customers according to their internal culture and traditions. At this point, the PQF can provide methodological support to the process of communication with the customer through product design. Today a variety of perceived quality attributes are in the spotlight of research interest for product development. For instance, according to Forslund, Karlsson, and Söderberg ( Citation2013 ), misaligned or improperly positioned split-lines (a combination of the following attributes describes a quality of a split line in PQF: ‘ Gap ,’ ‘ Flush ,’ ‘ Parallelism ’) negatively influence customer perception of a product. Hoffenson, Dagman, and Söderberg ( Citation2015 ), demonstrated a quantitative understanding of the customer-value split lines phenomena when evaluating product quality. While these experiments considered only single or just a few attributes – the PQF provides a holistic understanding of the design direction when speaking of a product’s perceived quality. Another example, illustrating the possibilities of PQF implementation, is the study presented by Skou and Munch ( Citation2016 ), investigating the values and aesthetics in ‘New Nordic’ design. This research provides an example of the ‘typical Scandinavian’ armchair, where ‘pressed plywood wraparound veneer not only functions as a comfortable armrest but is also the mechanism that holds the chair together.’ The particular armchair already depicts attributes included in the PQF, such as ‘ Gap ,’ ‘ Flush ,’ ‘ Surface Finish ,’ ‘ Material Pattern ’ and others related to the material, geometry, appearance, paint, joining qualities and solidity (see Section 3.2) The relative importance of these attributes can be assessed with the PQAIR method to give the designer a full understanding and control over the impactful areas of the product with regard to perceived quality.
Speaking of perceived quality, we are dealing with a complex, multifaceted adaptive system; a system where a human is the main agent. Therefore, as in any human adaptive system, single all-effective ‘causes’ cannot exist (Smil Citation2017 ). In this research, we justify the engineering viewpoint regarding perceived quality as an inevitable part of new product development. Making a product with excellent perceived quality is not an extremely difficult task for a product development project today – almost anything related to superior quality can be achieved with increased cost and time investments. The truly challenging task is to reach optimal perceived quality level based on given boundaries regarding technologies, development time, production systems capabilities, and financial limitations. For that reason, perceived quality must be controlled during all stages of product development. However, we were unable to identify up until now a framework or methodology which would explicitly define perceived quality and its elements and be able quantitively to assess the impact of a single perceived quality attribute on the product design as a whole. Ability to manage perceived quality can be expressed in the single open question, ‘ Which perceived quality attributes do engineers have to focus on to receive the highest level of a customer’s appreciation?’ This normative question is usually followed by the prescriptive question, ‘ How can we measure the importance of a single perceived quality attribute or a group of attributes for the customer?’ To address these questions, we propose a new method for perceived quality evaluation that can be applied to a variety of products. We present the Perceived Quality Framework (PQF), a taxonomy structure of perceived quality attributes and the Perceived Quality Attributes Importance Ranking (PQAIR) method . The PQF illustrates the attribute-centric engineering viewpoint on quality perception, developed through reciprocated studies of the automotive industry. The PQAIR method equips engineers with practical tools for perceived quality evaluation. The reason we have chosen the automotive industry is to set powerful goals. The automotive industry not only produces a complex product – the car, but it is a highly competitive production area itself and needs to spend its money on the right things to sustain competition. A combination of mechanical parts, software pieces, various types of materials, advanced manufacturing processes, and high production volumes make the automotive industry stand out in comparison to other sectors. We genuinely believe that the experience accumulated by the industry needs to be considered to maximise impact for researchers and their discoveries.
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2. Background
Considerable research, including various approaches to perceived quality, has been conducted primarily to attempt to identify the dimensions and nature of product quality (Olson and Jacoby Citation1972; Gilmore Citation1974; Crosby Citation1980; Garvin Citation1984; Zeithaml Citation1988; Steenkamp Citation1990; Reeves and Bednar Citation1994; Mitra and Golder Citation2006; Aaker Citation2009). However, this body of work, contributing mainly to the field of marketing and manufacturing science, has often depicted perceived quality as the antagonistic entity to the ‘real’ or ‘objective’ quality (i.e. not quantifiable, imaginary, subjective). Only recently, Golder, Mitra, and Moorman (Citation2012) proposed an integrative quality framework as a prominent approach to link the connections between objective and subjective quality domains. Alas, the engineering approach remains ambiguously defined. Hereafter, we describe the evolution of the views on perceived quality in product development and engineering practice. We begin with the obvious question, ‘What is a perceived quality?’
2.1. Definition of perceived quality from engineering viewpoint
Perceived quality is a multi-dimensional entity, an outcome of designer/customer convention, and can be seen differently by the different research schools of thought (e.g. philosophy, marketing science, engineering, manufacturing), so it is essential to set definitions.
There are several ‘marketing-oriented’ interpretations of perceived quality. For example, Mitra and Golder (Citation2006), see perceived quality as ‘perception of the customer’ and oppose it to the ‘objective’ quality. These views on perceived quality derive from the earlier research of Zeithaml (Citation1988), where perceived quality is defined as a subjective customer’s judgment (different from objective quality) regarding overall product superiority. A similar opinion is expressed by Aaker (Citation2009), defining the perceived quality as ‘the customer’s perception of the overall quality or superiority of a product or service with respect to its intended purpose, relative to alternatives.’ However, these definitions do not consider the engineering part in the equilibrium of perceived quality and instead focus solely on the customer. As a result, it is hard to start a meaningful discussion about the quantification of quality perception. From the engineering point of view, the perceived quality domain is a place where the product meaning, form, sensorial properties, and their execution intersect with human experience. Such an experience is driven by the interplay between product quality and its context. For example, in contrast to a rigid, formal definition of manufacturing quality – engineering tradition regarding perceived quality is to produce events that make the customer aware of how things are done. High perceived quality means attractiveness of the product to the customer. Yet attractiveness is a relative degree. It is based on our previous experiences and exists only in contrast to what does not attract attention (Falk et al. Citation2017). In industrial practice, engineers are continuously challenged with a polylemma of choice between equally important attributes and their performance; i.e. in the automotive industry should time and resources be invested in the minimisation of split lines gaps around rear lights of a car, or focused on a cut & sew execution of interior materials? At this point, we define engineering design intent as a rationale for product attributes that conveys the intrinsic requirements of the design. The equation, where engineering design intent is meeting customer’s expectations regarding the product, has to reach an equilibrium. Therefore, the correct perceived quality attributes prioritisation for the new product will lead to a successful design and customers’ appreciation.
Previously, we proposed a two-dimensional typology of perceived quality: Technical Perceived Quality (TPQ) and Value-based Perceived Quality (VPQ) (Stylidis, Wickman, and Söderberg Citation2015). TPQ includes everything that is part of a product (or service) and can be controlled by engineering specifications together with the functional product requirements (intrinsic attributes). VPQ is more related to brand image, brand heritage, affective customer judgments, hedonic or social values, the impact from other global attributes, advertising, and marketing promotion techniques (extrinsic attributes). Such a distinction is essential since perceived quality can be seen differently depending on the academic field. The attribute-centric approach to TPQ at the ‘bottom’ level, expressed with the Ground Attributes. The Ground Attributes are measurable variables, isolated for a specific product as they depict a borderline for meaningful discussion between designer/engineer and customer. The nature of Ground Attributes can be composite and may include materials, shapes, joining methods or parts; however, their primary purpose is to communicate engineering design intent effectively to the customer. The Ground Attributes have a further advantage – the ability to convey a meaning of perceived quality attributes as engineers see it. It is only uninformative (for the customer) technical specifications that are left beyond the Ground Attributes level. We want to stress that perceived quality attributes can also be defined differently by different OEMs; however, the overall goal of the attribute’s definition is to secure correct content and execution of the final product. All components and system solutions shall be built in such a way that the product is perceived as being one of high quality. This paper focuses on TPQ and its derivatives as previously defined in the theoretical description of the engineering approach to perceived quality.
2.2. Perceived quality as a part of product quality models
In engineering science the notion of perceived quality, similar to this research, appeared as a part of bigger models; i.e. in the field of Robust Design (Taguchi, Chowdhury, and Wu Citation2005) and particularly in the area of Geometrically Robust Design (Söderberg and Lindkvist Citation1999). These research methodologies were among the first to consider perceived quality as an aftereffect of manufacturing processes (Wickman and Söderberg Citation2007; Wagersten et al. Citation2011). Robust Design is widely recognised as a consistent methodology for obtaining a high level of product quality. Consequently, a Geometrically Robust Design has been defined by Söderberg and Lindkvist (Citation1999), as ‘a design that fulfills its functional requirements and meets its constraints even when geometry is afflicted with small manufacturing or operational variation.’ Concerning early design phases (usually described as a ‘fuzzy front end’), product requirements have a tendency towards ambiguity, with follow up difficulties in their quantification. This problem is a central issue for the automotive industry regarding the definition of perceived quality attributes. For this reason, it is important to set robust target requirements to avoid quality loss induced by variation. To address these issues, Pedersen, Christensen, and Howard (Citation2016) proposed the Robust Design Requirements Specification (RDRS) approach for quantification of the early stage requirements, and also developed the Perceptual Approach to Robust Design (Pedersen Citation2017). Howard et al. (Citation2017) introduced a Variation Management Framework (VMF), linking variation during production with its impact on product and customer perception regarding quality loss. For the most part, Robust Design recognises the need to control perceived quality, as geometrical variation can significantly influence the visual and tactile perception of the product. Although we see Geometrically Robust Design as the bedrock of PQF, it focuses mainly on the visual part of perceived quality (e.g. split-lines).
Another approach, widely recognised in the literature as Affective or Emotional Engineering, sees perceived quality as an affective impact of a product on the customer. This emotional impact is consequently analysed as a result of the composition of the various product attributes (Schütte Citation2002). Examples of methodologies that aim to measure the impact of affect caused by the product on the customer are Kansei Engineering, Positive Design, and Pleasure-based approaches in product design. Kansei Engineering (Nagamachi Citation1995) is a form of emotional engineering that translates the customers’ feelings about a new product into the design specifications. There are four primary points that need to be taken into consideration when applying Kansei methodology: (1) understanding the customer’s emotions regarding the product in terms of psychological estimation; (2) identification of design characteristics for the product; (3) establishing the connections between customers’ feelings and design characteristics in order to maximise customer satisfaction, and (4) product design adjustments to the current trends. However, Kansei methodology implementation is quite challenging in practice. It is limited to the analysis of words (usually adjectives) and their emotional representation of a customer’s perception. The difficulties in extracting and transforming customer emotions into technical specifications often lead to weak results; e.g. the technical and functional complexity of a car and its components usually exceeds the knowledge, imagination and verbal apparatus of an average customer. Moreover, engineers are usually poorly trained in the data analysis used in Kansei Engineering; there is a lack of support systems and guidelines (Nordgren and Aoyama Citation2007). In addition, a typical Kansei study is quite a time-consuming process (even if the experienced design team performs it), and this fact often plays a negative role due to a continuously shrinking time for the product development processes.
Desmet and Pohlmeyer (Citation2013) introduced the Framework for Positive Design, which comprises three major pillars: design for virtue, design for pleasure, and design for personal significance. Positive Design is a customer-centric approach and focuses on a deep understanding of the customer’s context, lifestyle, values, and goals related to the design process. However, this particular framework needs to be elaborated further towards the development of practical methods and tools for product development, especially at its early stages. Jordan (Citation2002) proposed linking product benefits or ‘pleasures’ to product attributes, moving human factors in design beyond the usability-based approaches. Jordan adopted a framework for addressing pleasure issues – ‘The four pleasures: a framework for considering pleasure with products.’ This framework defines four types of pleasures: (i) Physio-pleasure (ii) Socio-pleasure (iii) Psycho-pleasure, and (iv) Ideo-pleasure. However, the challenge to ‘fit’ the product correctly to the customer needs remains open. Therefore, with the plethora of available methodologies for the translation of ‘pleasures’ into design decisions, fitting can be applied only in the specific personal or usability context. Jordan divides these methods into empirical and non-empirical, describing advantages and limitations for each method. In essence, this new approach to human factors in design gives a broad overview of the existing methodologies. However, if applied in practice, exceptional skills and knowledge of the qualitative and quantitative approaches are required from the design team, which in turn is rarely the case. Zöller and Wartzack (Citation2017) proposed a methodology (ACADE) that integrates interdisciplinary knowledge into the product development process by addressing the subjective needs of a customer. ACADE was designed as a system to support subjective quality creation based on customers’ attitudes. The system’s workflow consists of three major phases: product context, user context, and processing. The subsequent data analysis includes numerical methods, such as multivariate statistical analysis, fuzzy set theory, and artificial neural network processing and analysis. At this point, the applied data analysis techniques are similar to those used in Kansei Engineering. However, the authors admit that only visual sensory perception factors have been considered to date and the possibility of the particular methodology application for assessment of other sensory systems is a question for future research.
Generally speaking there are few major flows in product development related to perceived quality (see Figure 1): the ‘old school’ manufacturing approach – not taking account of perceived quality; the ‘marketing’ approach – broadly customer-centric; the Emotional (Affective) engineering – subjective notion of perceived quality; the Robust Design and Geometrically Robust Design – although the engineering approach was introduced, it focuses mainly on visual quality. Alas, the comprehensive engineering approach, with a focus on perceived quality as a vantage point for new product development, together with questions regarding the importance of quantification, perceived quality attributes design impact on the customer – have not been widely covered in the literature, leaving a significant knowledge gap in applied and theoretical engineering science.
Perceived quality of products: a framework and attributes ranking method
Kostas
Stylidis
,
Casper
Wickman
&
Rikard
Söderberghttps://doi.org/10.1080/09544828.2019.1669769
Figure 1. Perspectives on product and perceived quality.
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Figure 1. Perspectives on product and perceived quality.
2.3. Towards quantification of perceived quality
The quantification and inquiry of the ability to measure perceived quality or its elements have recently become a prominent theme in research. Hazen et al. (Citation2017) presented a methodology for evaluation of the perceived quality of remanufactured products (PQRP), admitting that no attempts to measure the perceived quality of remanufactured products were made in the past. Li, Liu, and Li (Citation2014), proposed a method for customer satisfaction evaluation using Entropy weight and Analytic Hierarchy Process (Saaty Citation1990). This methodology combines the Kano model with the Entropy weight determination for product evaluation criteria, which in turn is assigned with the use of AHP. Thus, the industry professionals’ knowledge utilisation, combined with the use of statistical methods, forms a new path in perceived quality quantification methodology. Wiesner and Vajna (Citation2018) argue for low measurability of industrial design in the context of new product development, bridging the cognitive gaps between designers and users regarding the perception of wearable devices. Furthermore, several methods have been proposed for the evaluation of single attributes. Duraiswamy et al. (Citation2018) developed a methodology for robust evaluation of the perceived quality of vehicle body panel gaps or split lines. Pan et al. (Citation2016) presented a quantitative model for prediction of visual attraction design regions related to automotive styling, where customer’s response to product design was modelled with the use of a deep convolutional neural network and crowdsourced Markov chain. Overall, the research mentioned above shapes the current trend towards the quantification of perceived quality and development of the new approaches regarding the evaluation of entities that previously have been seen as highly subjective and non-measurable.
2.4. Perceived quality approach in the automotive industry
In the car industry, during the cycles of product development, the desired performance of the vehicle is handled by various product attributes, such as fuel consumption, passive and active safety, noise, vibration and harshness (NVH), durability, and weight. The perceived quality is usually one of these product attributes. Consequently, a typical automotive OEM uses around 20–120 perceived quality attributes, depending on organisational structure. The perceived quality attributes are responsible for the definition of requirements and requirement levels that determine the perceived quality of the product. In the car industry, these attributes can be associated with the complete vehicle requirements, but also the component and system-level requirements. Quite often, the perceived quality attributes are also responsible for complete vehicle verification with the use of computer-aided engineering, as well as physical testing. Notably, TPQ, as it is defined in this paper, is not usually administered in the industry as a single global product attribute but rather as distributed among many attributes, such as visibility, drivability, ergonomics, craftsmanship, etc. However, alone or in combination, thoroughly or with limitations, these global attributes can be described in terms of a common framework. Therefore, throughout this research paper, we consider TPQ as a global product attribute.
With this in mind, it is important to stress that despite the accumulated experience, long-term goals and working culture, advanced methods for quality control – the perceived quality evaluation often remaining ‘hit or miss’ action. Therefore, industry requires not only theoretical descriptions and delineation of perceived quality attributes but a ‘toolbox’ of assessment methods (preferably not a time-consuming and easy to understand).
2.5. Summary
The multifaceted nature of perceived quality recognised in research as well as in industrial practice. It has been addressed in different disciplines with a plethora of views and approaches. In this research, we identified major exploration pathlines in the area of perceived quality: (i) manufacturing-based; (ii) marketing-based (iii) emotional engineering; (iv) robust design and its derivatives; (v) industrial practice. Analysis of the vast literature leads to the development of the perceived quality attributes framework (PQF) and taxonomy of perceived quality attributes. Subsequently, the absence of the comprehensive methodology regarding perceived quality evaluation, primarily inspired by the current industrial needs, shaped the new method (PQAIR) for perceived quality attributes relative importance ranking (see Section 4). The newly developed method is aiming towards understanding how the engineering design intent decisions will impact on customer satisfaction, and consequently can be used to produce products with the high perceived quality. After all, the engineering-based concept of perceived quality has been introduced.
