  Widely used computer-aided translation (CAT) tools divide documents into
segments such as sentences and arrange them in a side-by-side, spreadsheet-like
view. We present the first controlled evaluation of these design choices on
translator performance, measuring speed and accuracy in three experimental text
processing tasks. We find significant evidence that sentence-by-sentence
presentation enables faster text reproduction and within-sentence error
identification compared to unsegmented text, and that a top-and-bottom
arrangement of source and target sentences enables faster text reproduction
compared to a side-by-side arrangement. For revision, on the other hand, our
results suggest that presenting unsegmented text results in the highest
accuracy and time efficiency. Our findings have direct implications for best
practices in designing CAT tools.
