In the wake of COVID-19, many districts have revisited a familiar question: should we expand instructional time to help students catch up? The instinct is understandable. If students lost learning opportunities during disruptions to in-person schooling, then “more time” can feel like the most direct solution.
Yet new evidence suggests the most important issue is not only how much time is scheduled, but how much time students actually receive—and how effectively schools can protect and use it. A September 2022 working paper by Matthew A. Kraft (Brown University) and Sarah Novicoff (Stanford University) provides one of the clearest syntheses to date on instructional time in U.S. public schools: how it compares internationally, how much it varies across schools, what research says about causal effects on achievement, and how much time is quietly lost inside the current day.
For school leaders, this research is especially relevant because it reframes the “add time” debate into a more actionable set of decisions: where time is inequitable, when added time is likely to help, and what operational changes can recover meaningful hours without rewriting the calendar.
1) The U.S. is not “behind” on time—on average
A long-running narrative claims U.S. students spend less time in school than peers in other high-income countries. Kraft and Novicoff complicate this view using international datasets from the OECD and PISA.
School year length: U.S. lower secondary schools average about 180 days per year, slightly below the OECD sample mean (about 184 days).
School day length: The U.S. tends to have longer school days—about 5.7 hours per day of instruction in OECD measures (above the sample average).
Total annual instructional time: When day length and year length are combined, the U.S. ranks relatively high in total hours among comparable countries.
The takeaway is not that time is irrelevant. It is that national averages can mislead. The more urgent story is what happens within the United States.
2) Instructional time varies dramatically across U.S. public schools
Using nationally representative survey data (the 2015–16 National Teacher and Principal Survey), the authors estimate the typical U.S. public school is in session about:
6.87 hours per day
178.71 days per year
1,227 total hours per year (total day length, not purely instructional minutes)
But the distribution is wide. The difference between schools at the 90th percentile and 10th percentile is about 190 hours per year—roughly five and a half weeks of schooling.
This matters for two reasons:
Equity: Students’ learning opportunities depend heavily on where they live and which school they attend.
Policy design: A one-size-fits-all push to expand time may be inefficient. Some schools already operate long schedules; others provide substantially less time than the national norm.
3) Why the variation happens: a patchwork of state rules and local choices
Unlike countries with centralized education ministries, the U.S. delegates authority to states—and states set minimum requirements in different ways. Some mandate days, some mandate hours, and some allow districts to meet either threshold.
The paper highlights how large these differences can be. For example, minimum high school instructional hours range widely across states. Over a student’s full high school career, these gaps can add up to the equivalent of many additional months of schooling.
Even within states, districts can extend time if budgets and labor agreements allow. Charter schools, in particular, are more likely to operate with extended schedules. The authors find charter schools average more total hours per year than traditional public schools, with a notable “upper tail” of urban charter schools running significantly longer days and/or years.
4) Does more instructional time improve achievement? The research says yes—but design matters
Kraft and Novicoff synthesize a large causal literature (not just correlational studies) and conclude that increasing instructional time can raise student achievement. However, effect sizes vary based on:
How time is added (year vs day vs subject-specific time)
How the time is used (quality, personalization, tutoring, coherence with curriculum)
Baseline conditions (systems with shorter days often show larger gains from expansion)
Two practical implications stand out for district planning:
Extending the school year often appears more effective than extending the school day in contexts like the U.S., where students already attend full-day schedules. One reason is implementation: adding days may require fewer changes to daily operations than adding hours.
Bundled approaches can be powerful when additional time is paired with strategies that increase instructional quality—such as tutoring, data-driven instruction, or targeted supports for students who are behind.
In other words, time behaves like other school resources: necessary, but not sufficient. The “return on time” depends on how well schools can convert scheduled minutes into focused learning.
5) The hidden opportunity: recovering lost learning time within the existing day
Perhaps the most actionable section of the paper is the case study of Providence Public School District (PPSD). The authors estimate how much instructional time is lost to factors such as:
Student absences (excused and unexcused)
Suspensions and tardies
Teacher absences
Outside interruptions (e.g., announcements, calls to classrooms)
Even with conservative assumptions, the estimated time loss is striking:
Elementary: about 16% of allocated instructional time lost
Middle school: about 21% lost
High school: about 25% lost
At the high school level, the authors estimate students can lose the equivalent of 258 hours per year—around 45 days of school—once absences, interruptions, and staffing gaps are accounted for.
This reframes the policy question. Before a district adds days, it can ask:
How much of our scheduled time is actually reaching students?
Which loss drivers are most preventable (interruptions, staffing coverage, attendance systems)?
Could targeted operational changes recover weeks of learning time without changing the calendar?
6) What this means for student support services—and where online therapy fits
Time is not lost only because of calendars. It is lost when students cannot attend, cannot engage, or cannot remain regulated enough to learn. Attendance challenges, behavioral incidents, and classroom disruptions often have underlying drivers—including anxiety, trauma exposure, communication needs, and unmet mental health or developmental supports.
This is where scalable student services can protect instructional time while improving access and equity. As a provider of online therapy services to schools, TinyEYE operates at the intersection of two needs highlighted by the research:
Reducing avoidable lost time: When students receive timely support (for example, speech-language services or mental health-related interventions), schools may see fewer instructional disruptions, fewer crisis-driven removals from class, and better day-to-day readiness to learn.
Making added time more effective: If a district extends learning time, the added minutes are most valuable when they include personalized supports—especially for students who are behind or who face barriers to participation.
Importantly, the paper’s core message is not “never add time.” It is “be strategic.” Districts can pair time strategies (like targeted year extensions, tutoring blocks, or schedule redesign) with student support systems that reduce the friction that causes time loss in the first place.
7) A practical decision framework for districts
Based on the evidence summarized in the working paper, district leaders can approach instructional time decisions with a simple set of steps:
Measure time accurately. Distinguish between allocated time (scheduled), potential time (teachers and students present, uninterrupted), and enacted time (students engaged).
Identify where time is inequitable. Schools operating far below typical hours may be candidates for expansion—especially if students have experienced significant learning loss.
Recover time before buying time. Address high-leverage loss drivers such as chronic absenteeism, frequent classroom interruptions, and coverage for teacher absences.
When adding time, protect quality. Use additional time for high-impact practices (e.g., tutoring, targeted literacy supports, structured small groups), not just “more of the same.”
Plan for sustainability. Consider staffing, burnout risk, and implementation complexity—particularly when extending the school day.
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