This publication is intended to help postsecondary schools understand FY 1999 draft cohort default rate data. It explains how the Department of Education calculates cohort default rates, the effect of cohort default rates, and how to read the cohort default rate loan record detail reports. Also, it reviews electronic reports available from the Department of Education; explains how to submit draft data challenges and participation rate index challenges; and defines the responsibilities of guaranty agencies. Following an introduction, sections of the report cover general information (cohort default rates, effects of cohort default rates, loan record detail reports, electronic loan record detail reports, and student repayment history reports); information on challenges (draft data challenges, participation rate index challenges); and information for guaranty agencies on challenges (general information, information on monthly status reports, draft data challenges, participation rate index challenges). Appended are guarantor/servicer contracts arranged numerically and alphabetically, extract file layout for electronic loan record detail reports and repayment information, message classes for electronic loan record detail reports, and a request for user comments on the guide. (EV)