ATOS ZPD (Zone of Proximal Development)

Students who have taken assessments are shown the ATOS ZPD reading range alongside the Star Score or the Lexile®* score. (The Building Administrator may turn off the Star Score in the building settings).

The Zone of Proximal Development (ZPD) is a term borrowed from psychologist Lev Vygotsky. In myON, the ZPD is a range of book levels that are not too challenging and not too easy, depending upon a student's reading level. It can help guide students' reading choices (but not limit those choices). The ZPD is shown in terms of ATOS book levels. These levels indicate how difficult a book is to read, and the first number shows the grade level associated with the book; for example, books with levels from 5.0–5.9 are at a fifth-grade level. ZPDs are also used in Accelerated Reader to help students find and select books.

The table below shows how ZPDs are selected based on some Grade Equivalent (GE) levels and Star Reading Enterprise Scaled Scores.

Star Reading Grade Equivalent scores range from 0.0 to 12.9+. They represent how a student's test performance compares with that of other students nationally. For example, if a 5th-grade student has a GE of 7.6, the student's score is equal to that of a typical 7th grader after the sixth month of the school year. This score doesn't necessarily mean that the student is capable of doing 7th-grade work - just that the student's skills are well above average for their grade level. GE levels below 1.0 represent Kindergarten and earlier levels.

In the table, you'll see a distinctive pattern. Above 2.0, the ZPD begins at a level that is lower than the GE - considerably lower as the GE goes up. This is because the GE from a test represents the highest level at which a student can read short passages, not the level at which the student can read comfortably for hours. Besides that, most noninstructional materials, even for adults, are written at 7th to 9th grade reading levels or lower. (John Steinbeck's The Grapes of Wrath, for example, has a book level of 4.9.) If students were asked to only read books that matched their GE, once they tested higher than about 6.0, they would be faced with very difficult, and probably not very enjoyable, material.

Grade-Equivalent Reading Score Suggested ATOS ZPD Reading Range Related Star Reading Enterprise Scaled Score Range
0 0–1.0 0–54
0.5 0.5–1.5 67–69
1.0 1.0-2.0 81–83
1.5 1.5-2.5 105–115
2.0 2.0–3.0 180–194
2.5 2.3–3.3 249–260
3.0 2.6–3.6 315–326
3.5 2.8–4.0 376–388
4.0 3.0–4.5 444–454
4.5 3.2–5.0 502–513
5.0 3.4–5.4 561–573
5.5 3.7–5.7 622–636
6.0 4.0–6.1 684–697
6.5 4.2–6.5 762–779
7.0 4.3–7.0 836–846
7.5 4.4–7.5 887–894
8.0 4.5–8.0 917–924
9.0 4.6–9.0 994–1014
10.0 4.7–10.0 1102–1106
11.0 4.8–11.0 1172–1175
12.0 4.9–12.0 1220–1223

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