This is because you can include all kinds of work produced by different pupils, or by same pupils at different times, in the same judging pot. (blog.nomoremarking.com)
The sensor on the iris scanner will allegedly be able to adjust its reading based on ambient light so that it can recognize the user's eyes even with different pupil sizes. (ibtimes.com)
This could be explored through the performance of secondary academies over a longer timeframe (e.g. five years or more), and of primary academies, including a comparison with non-academy schools with similar characteristics, and their impact on different pupil groups. (educationbusinessuk.net)