It is commonly acknowledged that service quality can be measured by using attribute-based and incident-based measurements. Both methods are distinct in nature, but can be used complementarily. However, in the literature a simultaneous empirical investigation of the power of critical incidents in relation to attribute scores is lacking. In this paper we merge both methods for assessing service quality in a professional services context. Subsequently, both measurements have been used to investigate the effect of service quality on short-term customer satisfaction and long-term trust in the service provider. Results indicate that the combined approach adds value to single-method measurement for explaining customer satisfaction. Furthermore, negative incidents are more influential on satisfaction than positive experiences. However, the negative effect of a negative incident on satisfaction can be compensated for by paying attention to particular dimensions of service quality. Critical incidents do not seem to have an impact on the apparently stable construct of trust.