All of Let's Go Learn's assessments are adaptive. So, as students advance in mathematics or reading, they are exposed to different items. In the case of reading with DORA, the passages rotate through three different forms. This way, if a student were to be given the same level passage, he or she would receive a new passage when re-tested.
In the Let's Go Learn technical manual, all assessments have undergone a test-retest analysis. This analysis took a statistically significant group of students and administered the same assessment (DORA, ADAM, or DOMA) two times within a 2-3 week period. The results were consistently no bias. This means students scored the same between the two testings, and the finding should eliminate any concerns about test bias from repeat administrations.
DORA series (Reading) assessment technical manual
ADAM/DOMA series (Math) assessment technical manual