Anyone who has worked as a teacher or principal in an elementary school understands the value of reliable and valid assessments of early reading progress. In order to implement an effective reading program, schools should have a coordinated plan for using screening, progress monitoring, diagnostics and outcome measures to guide instruction and to conduct program evaluation. One of the critical goals of the "Reading First" initiative in Florida is to increase the quality and frequency of reading assessments for all children in the early elementary grades. This Guide is designed to acquaint school principals with the assessment requirements of their "Reading First" grant. In order to successfully implement the assessment requirements of "Reading First," each school should: (1) have a team trained in the assessment procedures required by the grant; (2) have one or more assessment team members skilled in training others in the assessment procedures; (3) be able to organize the school for the assessment activities, working with teachers and administrators to meet the timelines for assessment; (4) be prepared to enter assessment data into a web-based data management system, interpret data reports produced by the data system; and (5) modify instruction and educational practices through an analysis of the student, classroom and grade-level reports generated by the web-based data management system. This Guide provides a plan for principals to follow in setting up and carrying out these assessment responsibilities. Principals of schools that do not have a "Reading First" grant but want to follow this assessment plan will find this Guide essential to effective implementation. The Guide explains the "Reading First" assessment requirements, the training model for preparing school staff to carry out the assessments, the procedures for ensuring that the student data are reliable, and the resources for interpreting and reporting the data. Appended is: Recommendations for the Use of Diagnostic Tests in Reading First Schools (Joseph K. Torgesen). (Contains 1 table.) [This document was produced by the Florida Center for Reading Research.]