The number of persistent absentees as a percentage of the total number of local authority maintained secondary school pupil enrolments. A persistent absentee is a pupil who has accumulated the threshold number of half-day sessions of absence over the relevant statistical reporting period - * an annual basis ? 64 or more half-day sessions of absence from school over the statistical reporting period for absence (this is currently the two and a half terms ending at the May half term); and * a two-term basis ? 52 or more half-day sessions of absence from school over the combined autumn and spring terms.