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 本帖最后由 snazkf 于 2013-10-5 11:04 编辑  
 
Following are some questions commonly asked about t 
he ATOS Readability Formula for Books. 
W h y d i d y o u c h a n g e r e a d a b i l i t y f o r m u l a s ? 
We wanted to provide educators with an easier-to-us 
e and more accurate tool for guiding students to 
appropriate books. We devoted two years of research 
to creating the ATOS readability formula. ATOS is 
more accurate than other formulas because: 
• 
It’s based on actual student book reading (we analy 
zed the reading of almost 1,000,000 books by 
more than 30,000 students). 
• 
It takes book length into account. 
• 
It employs the three statistics that researchers ha 
ve found to be most predictive of reading difficult 
y: 
the number of words per sentence, the number of cha 
racters per word, and the average grade level 
of the words in the book 
. 
W h a t d o e s a n A T O S b o o k l e v e l n u m b e r r e f l e c t ? 
An ATOS level on a book indicates how difficult the 
text is to read. Thus it helps you match books to 
a 
student’s reading level. But ATOS measures only the 
text. It does not—nor does any other readability 
formula—take into account literary merit, sophistic 
ation of ideas, developmental appropriateness, or 
maturity of theme or language. This is why it’s imp 
ortant to know and use three measurements: Readabil 
ity 
or Book Level (the difficulty of a book’s text), Re 
ading Level (a student’s tested level), and Interes 
t Level 
(the content level of a book). 
J u s t h o w a c c u r a t e i s A T O S ? 
ATOS correlates well with other standard readabilit 
y formulas and does a better job than other formula 
s with 
problematic types of books, such as high-low, emerg 
ent-reader, and nonfiction books. But it’s importan 
t to 
remember that all readability formulas produce only 
an estimate of a book’s readability based on selec 
ted 
variables in the text. Different formulas applied t 
o the same book will generally give estimates that 
differ by 
a grade level or so. Also keep in mind, as stated a 
bove, that readability formulas do not measure the 
maturity 
level of the content. That’s why we also indicate e 
ach book’s Interest Level to help you guide student 
s to 
appropriate content. In addition, an educator’s kno 
wledge of books is always an important factor when 
matching books to students. 
W h a t d o e s I n t e r e s t L e v e l m e a n ? 
The ATOS Book Level and the Interest Level represen 
t the two dimensions of reading: text and content. 
ATOS levels measure readability, or textual difficu 
lty. Interest Levels refer to the sophistication of 
a book’s 
content, ideas, and theme, and are based on publish 
er recommendations. A simple rule: use the ATOS lev 
el 
to determine whether a student can read the book an 
d Interest Level to help determine whether a studen 
t 
should read it. You can see the Interest Levels for 
books that have an Accelerated Reader (AR) quiz by 
looking through the title listings in the software, 
searching for the quiz on our Web site, or searchi 
ng in AR 
BookGuide or AR BookFinder.  |   
 
 
 
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