Comparison of two text entry methods on interactive TV

This paper describes a study with 18 participants on two text input methods for use with interactive television, The Numpad Typer (TNT) and TwiceTap. Both methods were designed for use with a common infra-red remote control. Each character is entered using two keystrokes. After one hour and forty minutes of practice, split into 5 sessions, the participants were able to type faster than 9 words per minute. While the performance of both methods was similar, the TwiceTap required a smaller number of keystrokes per character, was less prone to errors, and was found to be more comfortable by the participants. Over time, the use of frequent n-grams in TwiceTap was reinforced while the use of infrequent n-grams was suppressed.