i-Ready vs FastBridge

i-Ready and FastBridge are both used to understand student achievement, but they are built around different assessment models. i-Ready Inform—known as i-Ready Diagnostic before the 2026–2027 school year—is a broad computer-adaptive Reading and Mathematics assessment that reports scale scores, grade-level placement, national percentiles, domains, and individualized growth targets. FastBridge is a Renaissance screening and progress-monitoring system that combines broad computer-adaptive tests with brief curriculum-based measures across reading, mathematics, and social-emotional behavior.

The comparison is not simply “one test versus another.” A school giving i-Ready Reading is usually referring to one adaptive Inform assessment. A school using FastBridge might administer aReading, CBMreading, earlyReading, AUTOreading, aMath, earlyMath, or one of several CBMmath measures. Those FastBridge assessments answer different questions and can use different score units. Before interpreting a number, families must identify the exact measure.

The most important warning is this: an i-Ready score cannot be directly converted into a FastBridge score with a homemade table. A 500, 550, or 600 on i-Ready does not equal one fixed aReading or aMath score, percentile, or FastBridge risk category. Grade, subject, screening season, measure, norms, and local benchmark settings all matter. This guide explains the scores responsibly and shows how schools can use both systems within instruction and MTSS.

i-Ready vs FastBridge at a glance

What is i-Ready Inform?

i-Ready Inform is Curriculum Associates’ adaptive assessment for Reading and Mathematics in Grades K–12. For many years it was called i-Ready Diagnostic. Starting in the 2026–2027 school year, Curriculum Associates changed the name to i-Ready Inform to emphasize the assessment’s instructional purpose. Families may still see “Diagnostic” in older reports or hear educators use the familiar name; both refer to the adaptive assessment at the center of the current i-Ready Assessment suite.

The assessment adjusts item difficulty while a student works. Correct responses generally allow the system to explore harder skills, while incorrect responses help it locate prerequisite needs. Students should encounter questions they do not know. That challenge is part of measuring the upper boundary of current performance and should not be interpreted as proof that a child was taught the wrong material.

Schools commonly administer i-Ready in three windows: beginning of year, middle of year, and end of year. Teachers use the report to understand overall performance, placement relative to the student’s grade, skill-domain patterns, and growth toward individualized targets. The platform also connects results to instructional groupings and resources.

For a fuller introduction, read RevisionTown’s What Is i-Ready Inform? and How to Read an i-Ready Diagnostic Report.

What is FastBridge?

FastBridge is Renaissance’s pre-K–12 universal-screening and progress-monitoring system. It includes academic assessments in reading and mathematics as well as social-emotional behavior measures. Schools often use FastBridge within a Multi-Tiered System of Supports (MTSS) or Response to Intervention (RTI) framework to answer four practical questions:

1. Which students are likely to meet later learning goals?
2. Which students may need additional support?
3. Which specific skill appears to be limiting progress?
4. Is an intervention producing improvement quickly enough?

FastBridge is distinctive because it places computer-adaptive tests and curriculum-based measures in the same system. A broad CAT such as aReading or aMath estimates general achievement efficiently. A CBM samples a narrower skill through a short, standardized task that can be repeated with equivalent forms. The combination helps a school screen everyone, investigate a particular need, and monitor response to intervention without repeatedly giving a long broad assessment.

FastBridge should not be confused with Florida FAST, the Florida Assessment of Student Thinking. In this article, FastBridge means the Renaissance assessment system used by participating schools across the United States.

FastBridge is a suite, not one score

This is the key to reading any FastBridge report. The word “FastBridge” does not identify the exact assessment. A family might receive results from one or more measures, each designed for a different grade range and purpose.

Common FastBridge reading measures

• aReading: a computer-adaptive broad reading screener for Grades K–12; Renaissance lists an estimated 15–40 minutes.
• AUTOreading: brief computer-based measures of automaticity in areas such as letter names, letter sounds, decoding, word identification, spelling, vocabulary, and morphology; listed at 2–6 minutes.
• CBMreading: a teacher-administered oral-reading measure for Grades 1–8, usually 1–3 minutes.
• earlyReading: a set of foundational reading measures focused mainly on pre-K through Grade 1, commonly 1–4 minutes per selected task.
• COMPefficiency: a computer-based reading-comprehension efficiency measure for Grades 2–8, listed at 7–12 minutes.
• CBMcomp: a supplemental fluency and comprehension measure using recall and questions, listed at 5–10 minutes.

Common FastBridge mathematics measures

• aMath: a broad K–12 computer-adaptive mathematics screener, listed at 20–30 minutes.
• earlyMath: brief early-numeracy measures for K–1, with some uses in pre-K or above Grade 1 for students needing targeted support; listed at 1–4 minutes.
• CBMmath Automaticity: short computer-administered measures of arithmetic fact fluency for Grades 1–12; listed at about 4 minutes.
• CBMmath Process: teacher-administered multi-step computation measures primarily reflecting Grades 2–6 skills; listed at 10–15 minutes.
• CBMmath Concepts & Applications: grade-leveled measures of concepts and applied problem solving for Grades K–8; listed at 15–30 minutes.

A score from aReading is not on the same scale as a CBMreading result, and aMath is not interchangeable with CBMmath Automaticity. Ask for the assessment name before searching for a chart or comparing results.

Computer-adaptive tests vs curriculum-based measures

A computer-adaptive test selects later items partly from earlier performance. It can cover a broad range of achievement efficiently because not every student receives the same questions. i-Ready Inform, FastBridge aReading, and FastBridge aMath all use adaptive designs, but each has its own item bank, scale, stopping rules, content blueprint, and norms.

A curriculum-based measure is intentionally brief and highly standardized. It often focuses on a skill that can be sampled repeatedly, such as oral-reading fluency, decoding automaticity, math facts, or written computational procedures. Equivalent forms help educators draw a trend line across frequent administrations. A CBM is useful because it is sensitive to change, not because it diagnoses every possible cause of a low score.

i-Ready’s core Inform assessment is broader than a one- to four-minute CBM. FastBridge’s design lets a district pair a broad screener with narrower measures. Therefore, statements such as “FastBridge is shorter than i-Ready” are only partly true: many FastBridge CBMs are much shorter, while aReading and aMath are broader adaptive screeners with longer testing times.

How often are i-Ready and FastBridge given?

Both systems are commonly used for universal screening three times per year. The fall window establishes a beginning-of-year baseline, the winter window checks progress, and the spring window summarizes later-year performance. Each district controls its calendar, so the exact weeks vary.

The major difference appears after screening. A student receiving an intervention may complete a selected FastBridge progress-monitoring measure frequently—often weekly, according to the FastBridge family glossary. Repeated data points can show whether the score trend is moving toward the goal. Renaissance describes its FAST Projection approach as supporting actionable intervention decisions with as few as six data points.

Schools should not give the full i-Ready Inform assessment every week. Its broad adaptive result is usually interpreted across the main seasonal windows. The wider i-Ready Assessment suite includes additional tasks and standards measures that schools may use between those administrations, but those tools should not be confused with the Inform scale score.

Testing time and student experience

i-Ready Inform is student-facing and computer adaptive. Completion time varies by grade, subject, the 2026–2027 design, and individual pace. Schools frequently plan a larger block or divide the assessment into sessions. The student answers a broad sequence of Reading or Mathematics items, including questions above and below current performance.

FastBridge experiences vary widely. aReading and aMath are also computer adaptive. CBMreading and several other measures require a teacher to administer or score a standardized task. Some assessments last only a few minutes; others take 15–40 minutes. A student could therefore complete several different FastBridge tasks within a screening window.

Neither system should be judged by time alone. A very short duration can be appropriate for a CBM designed to last one minute, while the same duration would be suspicious for a 25-item adaptive screener. Families should compare actual time with the official expectation for the named measure.

i-Ready scores explained

Scale score

The i-Ready scale score is the central number on the Inform report. It places performance on i-Ready’s continuous Reading or Mathematics scale so growth can be examined across administrations. The number is meaningful only with the subject, grade, and testing season.

Grade-level placement

Placement translates the scale score into a criterion-referenced statement about performance relative to enrolled-grade expectations. Current i-Ready resources describe placements such as above grade level, on grade level, one grade level below, and two or more grade levels below, with detailed five-level reporting. Placement is an instructional description, not a recommendation to retain or accelerate a student by itself.

Percentile rank

The i-Ready percentile compares the student with a national same-grade group testing at a similar season. The 60th percentile means the score was as high as or higher than approximately 60 percent of that comparison group. It is not the percentage of questions answered correctly.

Typical Growth and Stretch Growth

Typical Growth is an individualized annual benchmark based on students with a similar starting point. Stretch Growth is a more ambitious target intended to help students move toward or beyond grade-level proficiency. These are i-Ready-specific targets and should not be copied onto a FastBridge report.

Domains

i-Ready reports performance across instructional domains. Reading can include foundational skills, vocabulary, and comprehension; Mathematics commonly includes Number and Operations, Algebra and Algebraic Thinking, Measurement and Data, and Geometry. Teachers use these patterns with classroom evidence to identify next steps.

FastBridge scores explained

Measure-specific score

FastBridge first reports performance in the unit used by the selected assessment. Broad adaptive tests such as aReading and aMath have their own scores. A fluency or automaticity CBM can report a count, rate, accuracy, or composite suited to that task. Because the unit changes by measure, there is no single “FastBridge scale score” that can describe the entire suite.

National percentile

Many FastBridge reports show a national percentile based on same-grade performance for the relevant season. FastBridge publishes seasonal norms for fall, winter, and spring. A percentile must therefore be read with the assessment and window. The 40th percentile on aMath does not mean the student earned 40 percent correct, and it is not automatically equivalent to the 40th percentile on i-Ready.

Local comparisons

The FastBridge Family Report can compare a student with other students in the district and across the country. Educator reports may also provide class, school, district, and national ranks when participation rules for the local group are met. Local norms describe performance within the current instructional context; national norms provide a broader comparison.

Benchmark and risk category

FastBridge converts screening performance into benchmark categories designed to indicate risk of not meeting later learning goals. The commonly used default framework is:

Exact benchmark scores vary by assessment, grade, and season. Districts can also apply approved custom benchmarks, so two districts may display different risk categories for a similar score. A risk label is a screening decision aid, not a medical diagnosis, disability determination, or permanent description of a child.

Progress-monitoring trend

A FastBridge progress-monitoring report can show a start score, goal, expected goal line, observed scores, and a trend or rate of improvement. Educators examine whether the trend is steep enough to reach the goal. A single low weekly point may reflect normal variability; a consistent pattern across several data points is more informative.

Typical Growth vs rate of improvement

i-Ready Typical Growth and Stretch Growth summarize individualized annual expectations from the beginning-of-year Inform result. A report may show how much of each annual target has been achieved. The focus is broad Reading or Mathematics growth across major administrations.

FastBridge progress monitoring focuses on repeated performance in a selected measure. A teacher may compare the student’s observed trend with a goal line or expected rate of improvement. This is especially useful for deciding whether a specific intervention should continue, change, intensify, or fade.

The two growth concepts cannot be equated. A student could meet i-Ready Typical Growth yet show an insufficient weekly CBMreading trend if the intervention goal is particularly ambitious or the measures capture different skills. Another student could make a strong FastBridge fluency gain while the broader i-Ready Reading score changes modestly because comprehension or vocabulary remains a need.

Learn more about i-Ready’s targets in Typical Growth vs Stretch Growth and see how season affects interpretation in i-Ready Fall vs Winter vs Spring Scores.

Reading comparison

i-Ready Reading gives a broad adaptive picture and reports instructional domains. It can identify whether performance is being limited by foundational reading skills, vocabulary, or comprehension. The same assessment framework supports comparison across the school year.

FastBridge Reading offers both breadth and narrow skill measurement. aReading estimates broad reading ability. earlyReading samples foundational skills for beginning readers. CBMreading lets a teacher hear oral reading and examine fluency. AUTOreading measures automaticity across decoding, word identification, spelling, vocabulary, and related subtests. COMPefficiency and CBMcomp add comprehension-focused evidence.

For a student with a low broad score, FastBridge’s multiple measures can help a team test a hypothesis about why. However, more scores do not automatically produce a diagnosis. Teachers still need error patterns, classroom reading, language background, instructional history, and observation.

Mathematics comparison

i-Ready Mathematics provides an overall adaptive score plus domain placements across major progressions. It is especially useful for seeing whether a student’s broad mathematics performance is on grade level and which domain requires attention.

FastBridge aMath also provides a broad adaptive estimate. Other FastBridge measures focus on narrower outcomes: early numeracy, arithmetic automaticity, written procedures, or concepts and applications. A student might be strong in conceptual problem solving but slow in math facts, or fluent with facts but weak in multi-step application. Selecting the correct measure helps the school distinguish those patterns.

The best instructional decision usually combines the broad result with a targeted measure and student work. A low automaticity score should not lead to fluency drills if the real barrier is conceptual misunderstanding; a low broad score should not be explained entirely by one brief computation task.

Universal screening and MTSS decisions

Universal screening means assessing all students with an efficient, standardized measure to identify who may need additional support. It is the first step, not the final eligibility decision. Both i-Ready and FastBridge can contribute to screening, and FastBridge explicitly organizes its product around screening, Tier 1 planning, Tier 2 or Tier 3 intervention, and progress monitoring.

A responsible MTSS process uses multiple sources. The team may examine the screening benchmark, national and local norms, classroom work, attendance, language, opportunity to learn, prior intervention, and teacher judgment. Students close to a cut score deserve the same thoughtful review as students farther away because all assessments contain measurement error.

If a district uses custom FastBridge benchmarks, families should ask which benchmark set appears on the report. If a school uses i-Ready placement or percentile cutoffs for intervention, ask whether the rule differs by grade, season, or subject. A colored band is not self-explanatory without the decision rule behind it.

Can you convert i-Ready scores to FastBridge scores?

No universal conversion is defensible. A statement such as “i-Ready 550 equals aMath 220” ignores grade, season, item design, scale construction, and uncertainty. It also ignores that aMath is only one FastBridge assessment. There is no sensible equation from an i-Ready Reading score to CBMreading fluency or from i-Ready Math to every FastBridge math measure.

Percentiles do not solve the problem. If a student is at the 60th percentile in both systems, the two scores indicate similar relative standing within their respective norm groups, not identical knowledge or guaranteed agreement. Norm samples, testing dates, content, and rounding can differ.

A district may rely on a validated linking or classification study to estimate the probability that students at a certain score will meet a later state benchmark. That model should identify the exact assessment version, grade, subject, season, sample, and outcome. Prediction is not direct conversion, and the probability should not be presented as certainty.

Which assessment is better?

Neither product is universally better; the answer depends on the decision a school needs to make.

• i-Ready may fit well when a district wants one broad adaptive Reading and Mathematics assessment, clear grade-level placement, domain reporting, individualized annual growth targets, and close connection to i-Ready instructional resources.
• FastBridge may fit well when a district wants a flexible menu of CAT and CBM screeners, very brief skill measures, frequent intervention progress monitoring, local and national comparisons, and academic plus SEB options in an MTSS framework.
• Using both may make sense when each fills a clearly defined role without unnecessary duplicate testing—for example, a broad seasonal assessment plus a brief intervention measure.

The strongest implementation has a written assessment purpose, calendar, decision rules, staff training, and a plan to act on results. More testing is not automatically better. If two tools answer the same question without changing instruction, the school should reconsider the burden.

What counts as a good score?

On i-Ready, an on-grade-level placement is a positive achievement signal, while progress toward Typical or Stretch Growth adds context for students starting above or below expectations. The best interpretation includes current achievement and improvement.

On FastBridge, a Low Risk benchmark generally suggests that the student is likely to meet the later goal under the system’s decision rules. Some Risk or High Risk indicates a need for closer review and possibly additional support. Because districts may customize benchmarks, check the legend on the actual report.

A strong score should never end the conversation. A student can be Low Risk overall and still need support in one skill. A student in High Risk can show excellent response to intervention. “Good” should mean the evidence is understood, growth is supported, and the next instructional step is appropriate.

What if the results disagree?

First identify the exact FastBridge measure and match the subject. Comparing i-Ready Reading with aMath is meaningless; comparing i-Ready Reading with a one-minute oral-reading measure is informative only about their shared reading relationship, not total equivalence.

Second compare dates. A fall i-Ready score and a spring FastBridge score reflect different amounts of instruction. Seasonal norms and benchmark expectations also rise. Third, examine testing conditions: illness, rushing, interruptions, device problems, unfamiliar administration, or weak engagement can affect a result.

Finally, look at the skill pattern. A student may perform adequately on broad comprehension but show low oral-reading automaticity. Another may read fluently but struggle with vocabulary and complex text. In math, broad reasoning and fact automaticity can diverge. Classroom work, error analysis, and teacher observation help determine which explanation fits.

How parents should read both reports together

1. Record the full assessment name. Write “i-Ready Inform Reading,” “FastBridge aReading,” or “FastBridge CBMreading,” not only the platform.
2. Note grade, date, and season. Fall, winter, and spring norms differ.
3. Interpret each report separately. Read i-Ready placement and FastBridge benchmark/risk using their own manuals.
4. Separate score from percentile. Neither percentile is percent correct.
5. Compare broad with broad. i-Ready Reading aligns more naturally with aReading than with one narrow CBM, but the scales still do not convert.
6. Use narrow measures to explain, not replace. A CBM can illuminate a specific skill behind a broad result.
7. Ask which norms and benchmarks are active. FastBridge reports may include local and national comparisons or district-customized cut scores.
8. Review several progress points. Avoid changing intervention because of one unusually high or low weekly score.
9. Connect data to action. Ask what instruction, intervention, practice frequency, and review date follow from the result.

Questions to ask the teacher

• Which exact FastBridge assessment produced this score?
• Was it universal screening or progress monitoring?
• What does the score unit measure?
• Which national norm year and screening season apply?
• Does the district use default or custom FastBridge benchmarks?
• How does the result compare with i-Ready domains and classroom work?
• What evidence suggests the student needs Tier 1, Tier 2, or Tier 3 support?
• Which skill will the intervention target?
• How often will progress be measured, and after how many data points will the team review the trend?
• What would count as enough improvement to continue, fade, or change the intervention?

Frequently asked questions

Is FastBridge the same as i-Ready?

No. i-Ready Inform is a broad adaptive Reading and Mathematics assessment with placement and annual growth targets. FastBridge is a suite combining CAT and CBM measures for screening and frequent progress monitoring.

Is FastBridge the Florida FAST test?

No. FastBridge is a Renaissance assessment system. Florida FAST is the Florida Assessment of Student Thinking, a statewide testing program.

Are both assessments adaptive?

i-Ready Inform is adaptive. FastBridge aReading and aMath are adaptive, but many other FastBridge measures are curriculum-based measures rather than broad adaptive tests.

Does FastBridge report grade-level placement?

The FastBridge Family Report emphasizes benchmark, district comparison, national comparison, and change over time. Renaissance notes that “grade level” can differ by state or district. Do not treat a FastBridge risk category as an i-Ready grade-level placement.

How often is FastBridge progress monitoring?

FastBridge describes progress monitoring as short weekly tests for a student participating in intervention, although the actual frequency should match the measure, intervention, and district plan.

Is the 40th percentile a passing score?

FastBridge commonly uses a benchmark around the 40th percentile as the boundary for Low Risk, but this is a screening risk framework, not a classroom passing grade. Exact benchmarks vary, and districts can customize them.

Can a student be on grade level in i-Ready but Some Risk in FastBridge?

Yes. The measures may assess different skills, use different norms, occur on different dates, or apply different cut scores. Review the named FastBridge measure and supporting classroom evidence.

Does a FastBridge percentile equal an i-Ready percentile?

No. The percentile values use each program’s norms. Similar percentiles describe similar relative standing within different reference groups, not identical achievement or content mastery.

Which score should parents trust?

Trust a pattern supported by multiple valid sources. Confirm administration quality, compare the measures’ purposes, inspect classroom work, and ask the teacher how the data informed instruction. Neither score should be used alone for a high-stakes conclusion.

Bottom line

i-Ready and FastBridge overlap in screening and instructional decision-making, but they organize information differently. i-Ready Inform provides one broad adaptive Reading or Mathematics profile with scale score, placement, percentile, domains, Typical Growth, and Stretch Growth. FastBridge provides a menu of broad CATs and brief CBMs with measure-specific scores, benchmarks, risk categories, norms, and progress-monitoring trends.

Use i-Ready to understand broad achievement, grade-level placement, domains, and annual growth. Use FastBridge to screen efficiently, examine selected skills, and monitor an intervention frequently. When both are available, let each answer the question it was designed to answer. Never force the scores into an unsupported conversion table.

Official sources

• Renaissance: FastBridge overview
• Renaissance: FastBridge Reading assessments
• Renaissance: FastBridge Mathematics assessments
• Renaissance: FastBridge family resources and glossary
• Renaissance Support: FastBridge benchmarks and norms
• Curriculum Associates: i-Ready Inform overview
• Curriculum Associates: i-Ready Inform resources for assessment leaders