A set of user interface design techniques for computer-assisted speech transcription are presented and evaluated with respect to task performance and usability. These techniques include error-correction mechanisms which originated in dictation systems and audio editors as well as new techniques developed by us which exploit specific characteristics of existing speech recognition technologies in order to facilitate transcription in settings that typically yield considerable recognition inaccuracy, such as when the speech to be transcribed was produced by different speakers. In particular, we describe a mechanism for dynamic propagation of user feedback which progressively adapts the system to different speakers and lexical contexts. Results of usability and performance evaluation trials indicate that feedback propagation, menu-based correction coupled with keyboard interaction and text-driven audio playback are positively perceived by users and result in improved transcript accuracy.