- CTA (Concurrent Think-Aloud): el usuario habla mientras se le graba con el ET
- RTA (Regresive Think-Aloud): el usuario, una vez grabada la sesión, ve el vídeo con las fijaciones marcadas (gaze-cued RTA) o sin ellas marcadas (video-cued RTA) y lo comenta
Studies have shown that gaze-cued RTA provides more feedback than Concurrent Think-Aloud protocol (CTA) in terms of the number of words spoken and comments made by participants [source (pdf)]. Researchers have also noted that gaze-cued RTA feedback tends to be of a higher quality than feedback obtained through CTA, resulting in the discovery of more usability issues. However, when gaze-cued RTA is compared to video-cued RTA (with no gaze overlay), the differences in user feedback are minimal. [source (pdf: pp 15 - 19)].