The measurement of service quality creates similar benefits and difficulties to that of satisfaction. According to accepted theory, satisfaction arises from a positive judgement of service quality received and costs incurred. The rationale for quality measurement is therefore that it focuses on the cause of satisfaction rather than the result, and therefore has greater diagnostic power. Two main models of service quality exist.
SERVQUAL
The SERVQUAL instrument is a questionnaire designed by Parasuraman, Zeithaml and Berry (1988). Its design is based on two principles:
• Customers’ judgements of service quality are made by comparing perceptions with expectations.
• These judgements are made on five quality dimensions of reliability, assurance, tangibles, empathy and responsiveness.
The questionnaire uses a Likert scale to gain customer ratings of both expected service and perceived service on each of these dimensions. Quality scores are then derived by subtracting expected quality ratings from perceived quality ratings. Scores may also be weighted to reflect the importance that customers place on each item.
SERVPERF
This competing model, offered by Cronin and Taylor (1992), disputes the two key principles underpinning SERVQUAL. Cronin and Taylor offer empirical evidence that the inclusion of expectations in the measurement of service quality is at best unnecessary, and at worst that it detracts from the reliability of quality ratings. Furthermore, the five dimensions of quality overlap. They advocate measuring perceptions of quality alone, and also recommend that each industry develops its own understanding of the quality dimensions as perceived by its customers.
Which to use?
Both measurement tools have their strengths and weaknesses, and the debate rumbles on in the academic literature. There is a good argument that the measurement of expectations increases the diagnostic power of service quality measurement, by capturing the standards against which the customer is judging the supplier, as well as the perception of how the supplier performs (Parasuraman et al., 1994). However, the work of several researchers indicates that expectations are often poorly defined in customers’ minds, and are not a reliable benchmark against which to measure quality (e.g. Teas 1993). Hence SERVPERF may provide a more reliable performance measure of service quality.
There is also general agreement that the five dimensions of quality defined by Parasuraman et al. differ from industry to industry (e.g. Teas, 1993; Carman, 1990; Shaw and Reed, 1999). Suppliers should, therefore, use focus groups to explore the dimensions on which their customers form quality expectations before embarking on a monitoring programme. This exercise should be repeated at regular intervals to ensure that the dimensions used remain relevant and comprehensive.