education.attendance-rate

def attendance_rate(possible_sessions: int, missed_sessions: int, on_date: str) -> AttendanceRate

@dataclass(frozen=True)
class AttendanceRate:
    """Attendance, absence and the DfE absence flags for one pupil."""

    #: 10000 minus absenceBasisPoints
    attendance_basis_points: int
    #: missed / possible, rounded half-up to a basis point
    absence_basis_points: int
    #: missed 10% or more of possible sessions
    persistently_absent: bool
    #: missed 50% or more; null on a date before that measure was published
    severely_absent: Optional[bool]

from fune.education.attendance_rate import attendance_rate  # education.attendance-rate@^1

from typing import Optional

from .dates_add_days import parse_iso_date  ← from dates.add-days ^1.0.0 · built alongside by fune
from .education_attendance_rate_data import ABSENCE_THRESHOLDS, ABSENCE_THRESHOLDS_HISTORY, ABSENCE_THRESHOLDS_HORIZON  ← this capability’s own data, compiled from data/absence-thresholds.json into the same file by fune build
from .education_attendance_rate_types import AttendanceRate
from .math_round_div import round_div  ← from math.round-div ^1.0.0 · built alongside by fune


def _is_int(value: object) -> bool:
    return isinstance(value, int) and not isinstance(value, bool)


def _threshold_on(measure: str, on_date: str) -> Optional[int]:
    for r in ABSENCE_THRESHOLDS:
        if r.measure == measure and on_date >= r.valid_from and (r.valid_to is None or on_date <= r.valid_to):
            return r.basis_points
    return None


def attendance_rate(possible_sessions: int, missed_sessions: int, on_date: str) -> AttendanceRate:
    """Attendance and absence in basis points, and the DfE absence flags.

    The flags compare missed x 10000 with possible x threshold, exactly: a
    rate of 9.996% rounds to 10.00% but is not persistent absence.
    """
    if not _is_int(possible_sessions) or possible_sessions < 1:
        raise ValueError("possibleSessions must be a whole number of 1 or more, received %s" % (possible_sessions,))
    if not _is_int(missed_sessions) or missed_sessions < 0 or missed_sessions > possible_sessions:
        raise ValueError(
            "missedSessions must be a whole number from 0 to possibleSessions (%s), received %s"
            % (possible_sessions, missed_sessions)
        )
    parse_iso_date(on_date)
    persistent = _threshold_on("persistent", on_date)
    if persistent is None:
        if ABSENCE_THRESHOLDS_HISTORY != "full" and ABSENCE_THRESHOLDS_HORIZON is not None and on_date < ABSENCE_THRESHOLDS_HORIZON:
            raise ValueError(
                "no persistent absence definition on %s: this build was installed with history=%s, so it only carries rules from %s. "
                "Reinstall with history=full for earlier years." % (on_date, ABSENCE_THRESHOLDS_HISTORY, ABSENCE_THRESHOLDS_HORIZON)
            )
        raise ValueError("no persistent absence definition on %s" % (on_date,))
    severe = _threshold_on("severe", on_date)
    absence = round_div(missed_sessions * 10000, possible_sessions, "half-up")
    return AttendanceRate(
        attendance_basis_points=10000 - absence,
        absence_basis_points=absence,
        persistently_absent=missed_sessions * 10000 >= possible_sessions * persistent,
        severely_absent=None if severe is None else missed_sessions * 10000 >= possible_sessions * severe,
    )

Install

fune build

With that line in your source, in a Python project (language python in fune.project), fune build resolves it and its 2 dependencies, pins them in fune.lock, downloads only the Python package of each, and builds the code above into your project’s .fune/build, one readable file per capability with a header linking back here. Or pin a range in fune.project and build in one step:

fune add education.attendance-rate

The manifest, vectors and README with only the Python implementation. Install it without the registry with fune add ./education.attendance-rate-1.0.1-python.fune, or fetch it from a terminal with fune pull education.attendance-rate@1.0.1:python.

The whole function, every language, is one file too: education.attendance-rate-1.0.1.fune, 20,274 bytes, sha256 628cb864d801b56920bd73fdf860b8bf0b0145e5019b166523a736ed57a86b22. It installs into a project of any language.

# fune: before education.attendance-rate

# fune: after education.attendance-rate

# fune: replace dates.add-days in education.attendance-rate
# fune: replace math.round-div in education.attendance-rate

# fune: step education.attendance-rate after <n|label>

More from the author

- **Persistent absence**: missing 10% or more of the pupil's own possible sessions. This is the definition from the 2015/16 academic year. It was introduced in 2005/06 at 20%, and from 2010/11 was about 15% measured against a standard number of sessions rather than the pupil's own, which cannot be expressed as a percentage of one pupil's sessions; a date before 1 September 2015 is therefore refused rather than answered with today's rule. - **Severe absence**: missing 50% or more. The data carries it from the 2018/19 academic year, the first year for which the DfE statistics release reports it; before 1 September 2018 `severelyAbsent` is null.

Both are dated rows in `data/absence-thresholds.json`, and `onDate` picks the row in force.

## Decisions

- **The flags use the exact fraction.** A pupil who missed 250 of 2,501 sessions has an absence rate of 9.996%, which rounds to 1000 basis points, but is not persistently absent: 250 is less than 10% of 2,501. Comparing the rounded rate is the naive mistake; a vector pins it. - **Absence is rounded, attendance is derived.** Absence is rounded half-up to a basis point and attendance is 10000 minus that, so the two always add up to 100%. (Rounding both half-up gives 10001 when each sits on a half.) - Sessions are whatever the school counts: two per day (morning and afternoon) in England. Missed sessions include authorised and unauthorised absence, as the DfE measures do; pass only the sessions you want counted. - No possible sessions is an error: there is no rate to report.

## Sources

- Department for Education, "Pupil absence statistics: methodology" (Explore education statistics): definitions of persistent absence (10% or more of a pupil's own possible sessions, from 2015/16) and severe absence (50% or more), and the history of the persistent absence threshold: https://explore-education-statistics.service.gov.uk/methodology/pupil-absence-statistics-methodology - Department for Education, "Pupil absence in schools in England: 2018/19", the first release reporting severe absence: https://explore-education-statistics.service.gov.uk/find-statistics/pupil-absence-in-schools-in-england/2018-19

## Notices

Contains public sector information licensed under the Open Government Licence v3.0 (https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/).

1.0.1 adds its attribution notices (NOTICE). The code and the tests are unchanged.

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