Beyond the existing SERVQUAL-based research, the authors develop an alternative model of public service quality. The various sources of public service quality are explored and a new classification scheme formulated by using critical incidents technique. Four main qualities of public service are identified: process quality, outcome quality, design quality, and relationship quality. The findings suggest that the critical attributes of public service quality for customer satisfaction differ according to the types of customers in the public sector. Final customers (beneficiaries) give priority to the process and outcome qualities, whereas intermediary customers (social workers) have high regard for the design and relationship qualities.