Punctuality and Time Tracking for Locum and Supply Teachers: What the Evidence Shows

Supply and locum teachers exist to protect learning time when the regular teacher can't be there. In practice, the handover itself is often where time gets lost — a locum arrives on site but can't get into the building, doesn't know which room to go to, or spends the first ten minutes of the lesson working out logins instead of teaching. For schools already paying a premium for cover, that lost time is an expensive problem worth measuring and fixing.

Supply cover is a large and expensive part of school staffing

Spending on agency supply teachers in England reached £1.4 billion in 2023–24, according to the Department for Education. A CFE Research report commissioned by the DfE found that schools pay agencies daily fees averaging £218 for primary schools, £291 for secondary schools, and £270 for special schools — markups of 60%, 94%, and 88% respectively over what the supply teacher themselves is actually paid. Supply teachers, meanwhile, earn on average around 40% less than permanent colleagues doing the same work, and the same report describes cover staff as "largely dissatisfied" with pay and conditions.

That combination — high cost to the school, low pay and instability for the teacher — means every minute of a supply booking has to count. A late or disrupted start doesn't just waste teaching time; it erodes value the school has already paid a substantial premium for.

Why a few lost minutes matter more than they seem

The clearest evidence on the cost of lost teaching time comes from a widely-cited longitudinal study by economists Raegen Miller, Richard Murnane and John Willett (NBER Working Paper 13356, published in Educational Evaluation and Policy Analysis, 2008), which tracked teacher absence and achievement across one large urban US school district. Controlling for individual teacher effects, they found that every 10 days of teacher absence reduced students' maths achievement by roughly 3.3% of a standard deviation — an effect comparable to swapping a teacher for one with two to three fewer years of experience. Part of the mechanism they identified is that substitute cover rarely replaces lost instruction like-for-like: routines break down, and the substitute typically doesn't know the class's specific needs.

That's the case for a well-organised cover lesson. A cover lesson that also starts late compounds the problem on top of an already-weaker starting position — less contact time, on top of a less-informed instructor. Schools rarely track how many minutes are actually lost at the start of cover lessons, which means the cost is invisible in a way that absence rates and budgets are not.

The real cause usually isn't the locum teacher

It's tempting to frame late starts as a punctuality problem with the individual — but the union data suggests the opposite is usually true: supply staff are frequently set up to be late by the school's own onboarding process. NASUWT's Supply Teacher Annual Survey (England, 2024/25, 570 respondents) found that:

• 17% of supply teachers were not given login details or told how to access computers or what to do at the end of the school day
• 10% were not told who to report to, or where, on arrival
• 35% had not been given a tour of the site
• 36% had not been briefed on fire evacuation procedures
• 55% had not been given a risk assessment

None of that is a timekeeping failure by the teacher — it's a handover failure by the school. A supply teacher who arrives on time but then has to track down a member of staff to find their room, get a login, or work out where the fire exits are hasn't been "late"; the lesson has, because the check-in process gave them nothing to work with.

What digital time tracking actually fixes

A clock-in system on its own won't solve a broken handover process, but it does two things that matter specifically for cover staff:

It makes arrival — and the gap between arrival and lesson start — visible. A face recognition or app-based clock-in gives the school office a timestamped, unfalsifiable record of when a supply teacher physically arrived on site, distinct from when they made it to the classroom. That distinction matters: if cover staff are consistently arriving on time but starting lessons late, the fix is a better handover, not a stricter lateness policy. If they're arriving late, that's a different and much smaller problem to solve with the agency.

It attaches the practical information to the moment of arrival, not before it. Where the system supports it, pairing clock-in with a short digital briefing — room number, class list, login, fire procedure, who to report to — removes the single biggest cause the NASUWT data points to: supply teachers left to find things out for themselves. A locum who clocks in and immediately has that information on their phone or on the office screen starts the lesson faster than one who has to ask around.

There's a secondary, more familiar benefit too: identity-verified clocking (rather than a paper sign-in book or a shared login) removes any ambiguity about which staff member actually covered a given lesson and for how long — useful both for accurately paying agency invoices against the markups described above, and for safeguarding, since the school always has an accurate record of who was on site.

Emergencies: knowing who's on site, especially on large sites

The NASUWT data above showed that over a third of supply teachers arrive without a fire evacuation briefing. That's a punctuality and handover problem day-to-day, but it becomes a safety problem the moment there's an actual emergency. On a large secondary school or a multi-building MAT campus, a paper sign-in book at one reception desk can't tell you, in real time, who is currently on site, which building or room they're in, or whether that person is a permanent staff member, a supply teacher three hours into a booking, or a visitor who left an hour ago.

A digital, clock-in-based record fixes this by construction: every person on site — permanent staff, supply and locum teachers, contractors, visitors — has a live status the moment they've badged, scanned, or face-recognition clocked in, and it clears the moment they clock out. In an evacuation, that gives site leaders an accurate, exportable roll call instead of a headcount taken against a printed list that's already hours out of date. For supply staff specifically, it also means the school doesn't need to rely on the teacher remembering a verbal fire briefing they may or may not have been given — the system already knows they're in the building and where.

Managing access for one-off and recurring bookings

Most supply bookings are one-off, which leaves schools with an awkward choice: treat every locum as a full staff enrolment (unnecessary overhead for a single day's cover), or fall back on a paper sign-in book with no real identity check at all. Neither scales well, and neither handles the common middle case — a supply teacher a school ends up booking again and again — without either re-enrolling them from scratch each time or leaving old access sitting active indefinitely.

PunchIn handles this with visitor accounts that default to expiring at the end of the day they're created for. A school or agency can pre-register a locum's details and credential ahead of a booking, so the teacher can clock in and get access from the moment they arrive with no delay at reception — and by default, that access simply lapses at the end of the day rather than needing to be manually switched off. If the same teacher is booked again, the office isn't starting over: a visitor account with recurring bookings can be converted into a regular staff profile, which stays dormant between assignments and is enabled only for the specific day(s) actually booked. That gives schools accurate, per-day access with none of the enrolment friction of treating a familiar face as a brand-new visitor every time.

A practical checklist for schools and MATs

• Give every supply teacher a standard, written check-in pack (room, login, class list, site map, fire procedure, who to report to) tied to their clock-in, not handed over verbally on the day
• Record arrival time separately from lesson start time, so you can see where the gap actually occurs
• Use identity-verified clocking rather than a sign-in sheet — it removes disputes over hours worked, which matters when agency invoices are already carrying a large markup
• Make sure every person on site — including supply and visiting staff — is reflected in the live clock-in record, so a fire evacuation roll call is accurate rather than reliant on a printed list
• Pre-register one-off supply bookings as a visitor-style account set up before arrival day, and convert regular locums into a dormant permanent profile that's enabled only for the days they're actually booked
• Review recurring gaps between arrival and lesson start by site — a pattern usually points to a process issue (reception cover, key access, IT provisioning) rather than an individual
• Share attendance and punctuality data with the agency, not just complaints — agencies can act on patterns they can see

GDPR and data protection

As with any staff biometric or attendance data, schools remain the data controller for supply and locum staff records, including for teachers placed by an agency. You need a clear privacy notice available to agency staff before their first booking, a documented lawful basis, and confidence that the system encodes biometric templates rather than storing photographs. PunchIn acts as data processor; involve your DPO before extending clocking to agency-supplied staff, since consent and contractual arrangements differ from those for direct employees.

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Sources

• Department for Education / CFE Research, Analysis of the supply teacher market (2024), reported via Schools Week, September 2024
• Miller, R.T., Murnane, R.J. & Willett, J.B., "Do Teacher Absences Impact Student Achievement? Longitudinal Evidence from One Urban School District," NBER Working Paper No. 13356 (2007); published in Educational Evaluation and Policy Analysis, 30(2), 2008
• NASUWT, Supply Teacher Annual Survey — England 2024/25 (n=570)