Closing Achievement Gaps Through Accelerated Growth: What the Research Tells Us

The chart looked discouraging, but the principal was determined to find the silver lining. "Our students made growth!" she announced to the board. "Eighty percent of students met their growth targets."

A board member studied the data more carefully. "But the growth targets were set at the 50th percentile—average growth. If our students start below grade level and make average growth, doesn't that mean they stay below grade level?"

The room fell silent. The board member had identified the fundamental problem with celebrating "adequate" growth for students who are behind: adequate isn't enough. Students who start below grade level and make typical growth remain below grade level—year after year, until they graduate still behind.

Closing achievement gaps requires growth that is above average—sometimes dramatically above average. Understanding this math, and implementing practices that produce accelerated growth, is the central challenge of educational equity.

The Math of Gap-Closing

The arithmetic is straightforward but sobering. Consider a student who enters third grade reading at a first-grade level—two years behind. Each year, grade-level expectations advance. If our student grows at the same rate as her peers, she remains two years behind. To close the gap, she must grow faster than the students she's trying to catch.

The NWEA's analysis of pandemic recovery needs illustrates this clearly. They estimate that students lost an average of 4-5 months of learning during the pandemic. To recover this lost ground while keeping pace with current learning, students need approximately 4-5 additional months of instruction—equivalent to about a year of accelerated growth.

For students who were already behind before the pandemic, the required acceleration is even greater. A student who entered the pandemic two years behind and lost five months of learning now needs to close a 2.5-year gap—requiring 150%+ of typical growth for years to catch up.

What Produces Accelerated Growth?

If typical instruction produces typical growth, closing gaps requires something different. Research points to several interventions with demonstrated ability to produce above-average growth:

High-Dosage Tutoring

The strongest evidence for gap-closing acceleration comes from high-dosage tutoring—intensive, frequent, one-on-one or small-group instruction. Studies consistently show effect sizes of 0.3-0.4 standard deviations, equivalent to 4-6 months of additional learning per year.

"High-dosage" means frequent (at least 3 times per week, ideally daily) and sustained (over months, not weeks). Occasional tutoring helps but doesn't produce the accelerated growth needed to close significant gaps. The intensity matters.

Extended Learning Time

More time on task can produce more learning. Extended school days, summer learning programs, and after-school academics all offer opportunities for additional instruction. The research is mixed—quality matters more than quantity—but well-designed extended learning can contribute to accelerated growth.

The key is ensuring that extended time is used for effective instruction, not just more of the same. Extended time that repeats ineffective approaches doesn't help. Extended time with targeted, high-quality instruction does.

Diagnostic-Driven Instruction

Students behind grade level often have specific skill gaps that block further progress. A fifth-grader who never mastered multiplication facts will struggle with fractions, regardless of how well fractions are taught. Diagnostic assessment identifies these foundational gaps; targeted instruction addresses them.

This approach requires moving beyond grade-level-only instruction to address prerequisite skills students missed. It's not "remediation" in a punitive sense—it's building the foundation that makes grade-level success possible.

Acceleration Over Remediation

Counterintuitively, focusing on grade-level content with additional support often works better than pulling students back to below-grade-level work. Research by TNTP (The New Teacher Project) found that students given access to grade-level assignments learned more than those given below-level work, even when starting behind.

The strategy is "just-in-time" support: teach grade-level content while providing the specific scaffolding needed to access it. A student learning fractions who struggles with multiplication gets targeted support on multiplication within the context of fraction instruction—not pulled out for separate remediation that never catches up to where the class has moved.

Understanding Growth Disparities

Achievement gaps exist not only in where students are but in how fast they're growing. Research consistently finds that students from lower-income families and students of color often show lower growth rates than their more affluent white peers—meaning gaps widen over time even when growth is "positive."

These growth disparities have complex causes:

Opportunity gaps: Students may have less access to high-quality instruction, experienced teachers, rigorous curriculum, and enrichment opportunities. Less opportunity produces less growth.

Summer learning loss: Students from lower-income families typically lose more ground over summer, when higher-income peers are gaining. The school year growth rate may be similar, but summer differences accumulate.

Chronic absenteeism: Students who miss more school learn less. Chronic absenteeism rates are higher in high-poverty schools, contributing to growth disparities.

Unaddressed foundational gaps: Without intervention, foundational skill gaps block further progress. Students who can't decode fluently can't grow in reading comprehension regardless of instruction quality.

Addressing achievement gaps requires addressing these underlying causes, not just setting more ambitious targets for students who are behind.

School-Level Strategies for Accelerated Growth

Producing consistent accelerated growth for students who are behind requires school-wide commitment and systems:

Identify and Prioritize

Not every student needs accelerated growth—only those who are behind. Schools must systematically identify these students and ensure they receive the intensive support required. Growth data, not just proficiency status, should drive identification.

Allocate Resources Strategically

Accelerated growth requires resources: tutoring, intervention specialists, additional time. These resources must flow to students who need them most. Schools that spread resources evenly across all students—regardless of need—produce equitable access but not equitable outcomes.

Monitor Growth, Not Just Proficiency

Schools must track whether students who are behind are growing fast enough to catch up. Monitoring proficiency alone can mask that students are falling further behind. Growth monitoring for at-risk students should be frequent—at least quarterly, ideally monthly.

Protect Intervention Time

Intervention that gets squeezed out when other priorities arise doesn't produce results. Schools must protect scheduled intervention time the same way they protect core instruction. When students miss intervention for assemblies, testing, or schedule conflicts, accelerated growth becomes impossible.

Invest in Intervention Quality

More intervention time with ineffective programs doesn't help. Schools must ensure that intervention programs are evidence-based, that interventionists are well-trained, and that implementation is high-fidelity. Quality matters at least as much as quantity.

The Equity Imperative

Achievement gaps in American education correlate strongly with race and income. Students from low-income families and students of color are disproportionately likely to be behind grade level. Closing these gaps is thus fundamentally an equity issue.

But the required strategies—intensive tutoring, extended time, additional support—require resources. And resources in education are not distributed equitably. High-poverty schools often have less funding, less experienced teachers, and less access to intervention programs. The students who most need accelerated growth often have the least access to what produces it.

Changing this requires both school-level action and system-level advocacy. Schools must maximize what they can do within current resources while pushing for the resource equity that makes universal gap-closing possible.

Case Study: A District Approach

Jefferson County Schools serves a diverse district with significant achievement gaps. Three years ago, they launched a comprehensive gap-closing initiative:

Identification: Every student more than one year below grade level in reading or math was identified and assigned to intensive intervention. This was approximately 25% of the student population.

Intervention: Identified students received daily 30-minute tutoring sessions in small groups (1:4 ratio) with trained tutors using an evidence-based curriculum. This was in addition to—not instead of—core instruction.

Monitoring: Growth was assessed every six weeks. Students not showing adequate growth were moved to more intensive support (1:2 or 1:1 tutoring). Those showing strong growth could transition to less intensive maintenance support.

Summer: The highest-need students were offered an extended summer program focusing on maintaining and extending gains.

Results after three years: The percentage of students more than one year below grade level dropped from 25% to 14%. The growth rate for intervention students averaged 130% of typical. Achievement gaps by income and race narrowed by approximately 30%.

"We're not there yet," acknowledges Superintendent Maria Torres. "But for the first time, we're actually closing gaps instead of just talking about it. The key was committing to what the research says works—intensive, sustained intervention—and actually doing it at scale."

The Bottom Line

Achievement gaps don't close themselves. Typical growth maintains gaps; only accelerated growth closes them. Producing accelerated growth requires intensive intervention that most schools don't provide at sufficient scale.

The gap-closing formula is straightforward: identify students who are behind, provide evidence-based intensive support, monitor frequently, adjust when needed, sustain over time. The formula is simple; the execution is hard. It requires resources, commitment, and systems that most schools haven't built.

But the alternative—watching gaps persist year after year while celebrating "adequate growth"—is unacceptable. Students who enter behind and exit behind have been failed by a system that never invested what their success required. Doing better is possible. The question is whether we're willing to do what it takes.