Abstract
Chatbots are increasingly used in public service delivery, yet many remain difficult to use because their scope, conversational flow and persona are poorly designed. This study evaluates whether a human-centered design (HCD) approach can improve the usability of a Frequently Asked Questions (FAQ) chatbot developed for the Tanzania Ports Authority (TPA). The chatbot was designed iteratively through stakeholder consultation and expert input, with explicit attention to scope clarity, error handling, multi-turn flow and transparent persona design. Usability was assessed through heuristic evaluation, task-based testing and post-use questionnaires with 15 domain experts. The chatbot achieved a 95.1% weighted task success rate, decreasing task completion times across repeated sessions and high satisfaction ratings. The findings show that integrated attention to core chatbot design issues can improve public-service chatbot usability and provide a practical model for similar African and resource-constrained contexts.
