Half Moon Bay High: attendance

68 empty seats, every school day.

On an average day in 2024–25, about 68 of Half Moon Bay High's 911 students were not in school. Its district, Cabrillo Unified, is a basic aid district, funded by its own property taxes, so its revenue depends little on attendance.

68students absent on an average day

$966ka year in attendance funding those seats would bring

1 in 5students chronically absent (19.8%)

92.6%attendance rate; California 92.9%

2024–25. Attendance funding goes to Cabrillo Unified, so the empty seats are valued at the district's dollars per student. Method and sources at the foot of the page.

Enrolled, but not in school

Each bar is everyone enrolled that year. The blue part is how many were in school on an average day; the red part is how many were not.

In school on an average dayAbsent on an average day

Numbers on the bars: students absent on an average day. 2019–20 has no attendance data (COVID); 2020–21 was mostly distance learning.

What the empty seats are worth

California pays a school's district for each student in school on an average day (its Average Daily Attendance, or ADA). Each empty seat, valued at that year's dollars per ADA:

Hatched years: the state froze or protected attendance funding during COVID, so absences that year did not cut the money. Since 2022–23 a district is paid on the best of this year, last year or a three-year average, which softens a fall but also delays a rise.

What better attendance would bring

Attendance rate is the share of enrolled students in school on an average day. Move the slider to a higher rate: how many more seats would be filled, and what would Cabrillo Unified receive?

Attendance rate: 94.6%

18more students in school on an average day

3.6fewer days missed per student a year

$260kmore attendance funding a year, at 2024–25 rates

Half Moon Bay High's attendance rate in 2024–25 was 92.6%. Each point is worth the same wherever it starts, since it is a point of every enrolled student's days.

Who is missing

Some students carry far more of it

Groups too small for the state to report are left out. Foster youth and homeless students point to the transport, housing and family pressures outside school. They are real, and no school model removes them on its own.

Why days are missed

Of the days Half Moon Bay High students missed in 2024–25, 34% were unexcused, 65% excused (illness, appointments), 0% were independent study work not completed, and 1% were suspensions. In 2018–19, before COVID, 31% were unexcused. Unexcused absence, where no reason is given, is the kind most likely to reflect a student choosing not to come.

Behind, and staying away

Each dot is a school in Cabrillo Unified; Half Moon Bay High is the one ringed in black. Across, how far its students were from the state's math standard in spring 2025; up, the share chronically absent in 2024–25. Colour is the share of students from low-income families.

Under 60% low-income 60–90% 90% or more Charter school Alternative school (continuation, independent study) Half Moon Bay High

5 schools with at least 50 students. Correlation between math results and chronic absence: −0.81 across all of them. Dot size: enrollment. Hover a dot for the school.

What this does and doesn't show. Where students are furthest behind, absence runs highest. Where the link holds among places serving almost entirely low-income families, it isn't only family income. It fits the idea that discouraged students stay away. It can't show which comes first: missing school also puts students behind. Proving the direction is what the sponsored schools are for.

Students who left

Half Moon Bay High has 107 fewer students than in 2014–15. Its district, Cabrillo Unified, has 24.0% fewer. Had Half Moon Bay High changed at the district's pace it would have about 773; it has 911. A school's enrollment also moves with boundaries, programs and new schools nearby, so read this as a prompt to ask why rather than as a verdict. It has kept pace, so the opportunity is students who are enrolled and not coming.

Half Moon Bay HighCabrillo Unified

Enrollment as a share of 2014–15's. Census-day counts.

How we worked it out

Absent on an average day = every day of school missed by every student that year, divided by 180 school days. In school = census-day enrollment minus that. For 2024–25 this gives about 843 students in school on an average day.
Attendance rate = students in school on an average day ÷ students enrolled.
Dollars per ADA = LCFF revenue that year divided by funded ADA, from CDE's LCFF Summary Data: Cabrillo Unified's, since the district is paid for its schools' students. It includes the extra grants for low-income students and English learners, so it is what an added student brings, not the statewide base rate.
Years. The absence collection began in 2017–18, and some districts' figures jump the next year in a way that looks like a change in recording, so this page starts in 2018–19. 2019–20 has no attendance data (COVID). 2020–21 was mostly distance learning, when attendance meant something different.
Chronically absent is CDE's measure: a student who missed at least 10% of the days they were enrolled.
Sources: California Department of Education: Absenteeism by Reason and Chronic Absenteeism (DataQuest downloads), Census Day Enrollment, LCFF Summary Data, CAASPP research files and Free or Reduced Price Meal files.

The numbers behind the first two charts

Year	Enrolled	Days missed	Absent, average day	In school	Funded ADA	$ per ADA	Value of empty seats
2018–19	1,001	9,189	51	950	—	$9,193	$469k
2020–21	1,060	8,455	47	1,013	—	$10,155	$477k
2021–22	1,039	12,234	68	971	—	$10,290	$699k
2022–23	1,024	12,766	71	953	—	$11,358	$806k
2023–24	987	17,053	95	892	—	$13,407	$1.3M
2024–25	911	12,200	68	843	—	$14,247	$966k