Florida requires that students who do not meet grade-level reading proficiency standards on the end-of-year state assessment (Florida Comprehensive Assessment Test, FCAT) receive intensive reading intervention. With the stakes so high, teachers and principals are interested in using screening or diagnostic assessments to identify students with a strong likelihood of failing to meet grade-level proficiency standards on the FCAT. Since 2009 Florida has administered a set of interim assessments (Florida Assessments for Instruction in Reading, FAIR) three times a year (fall, winter, and spring) to obtain information on students' probability of meeting grade-level standards on the end-of-year FCAT. In 2010/11 the Florida Department of Education aligned the FCAT to new standards (Next Generation Sunshine State Standards) and renamed it the FCAT 2.0 but retained the 2009/10 cutscores. In 2011/12 it changed the FCAT 2.0 cutscores. The share of students meeting grade-level standards on the FCAT 2.0 fell to 53 percent in 2012 from 72 percent in 2011. This drop led the Florida Department of Education to partner with the Regional Educational Laboratory Southeast to analyze student performance on the FAIR reading comprehension screen and FCAT 2.0 to determine how well the FAIR and the 2011 FCAT 2.0 scores predict 2012 FCAT 2.0 performance. The study addresses two research questions: (1) What is the association between performance on the 2012 FCAT 2.0 and two scores from the FAIR reading comprehension screen across grades 4--10 and the three FAIR assessment periods (predictive validity)?; and (2) How much does adding the FAIR reading comprehension screen affect identification errors beyond those identified through 2011 FCAT 2.0 scores (screening accuracy)? Performance on the 2012 FCAT 2.0 was found to have a stronger correlation with FCAT success probability scores than with FAIR reading comprehension ability scores. In addition, using 2011 FCAT 2.0 scores alone to predict 2012 FCAT 2.0 scores underidentified 16-24 percent of students as at risk. Adding FAIR reading comprehension ability scores dropped the underidentification rate by 12-20 percentage points. An appendix provides additional statistics. (Contains 10 tables, 1 box, and 3 notes.) [This report was prepared for the Institute of Education Sciences (IES) by Regional Educational Laboratory Southeast administered by Florida Center for Reading Research, Florida State University.]