The Unified Scale accomplishes two different objectives. First, it links Star Early Literacy Enterprise to the Star Reading scale. Second, it creates a new scale, applicable to Early Literacy, Reading, and Math, that has the desirable measurement properties of a Rasch score scale. The Unified Scale provides you with increased measurement precision and one consistent scale across all computer-adaptive Star assessments.
In response to the need for one scale, Renaissance developed the "unified score scale" that can be used to report scores for both Star Early Literacy and Star Reading (as well as Star Math). The Unified Scale score range applies to both English and Spanish versions of the Star programs and ranges from 0 to approximately 1400; Star Early Literacy scores range from 200–1100 and Star Reading (and Star Math) range from 600–1400. Note that a single score does not apply across all programs—for example, a student having a score of 900 in Star Early Literacy cannot automatically be assumed to have the same score in Star Reading, Star Early Literacy Spanish, or any other Star program.
A note of caution is necessary here to discourage over-interpretation of this unified score scale: Although Star Early Literacy Enterprise and Star Reading Enterprise are fairly highly correlated, they measure different aspects of the progression from pre-literacy to fully-developed reading proficiency. Consequently, the highest claim that can be made about the Star Early Reading Rasch scores and scale scores is that they identify new Star Early Literacy scores that are approximately equivalent to Star Reading scores.
Related video: AssessMinutes—Unified Scale