Glossary

MTSS

MTSS — multi-tiered system of supports — is a framework for organising instruction and intervention into escalating tiers based on data, covering academics, behaviour and attendance in a single structure. It is a way of running a school, not something a district buys.

Last reviewed 2026-08-04 ยท Kastr is pre-launch; we publish dated status rather than logos.

The three tiers, and what each owes families
Tier 1Tier 2Tier 3
PopulationAll studentsRoughly 10–15%Roughly 3–5%
What it isEffective core instruction and school-wide practiceTargeted small-group support in addition to Tier 1Intensive, individualised, high-frequency
Data cadenceUniversal screening, typically three times a yearProgress monitoring every one to two weeksWeekly or more often
Owned byClassroom teacherGrade or subject teamProblem-solving or MTSS team
Family communicationGeneral, universal, informationalNotification that support has started, plus periodic progressIndividual meetings, documented plan, frequent contact
ConsentNot applicableNotification, not usually consentOften a formal meeting; special-education referral is a separate process

MTSS, RTI and PBIS — the scope difference

These three terms are used interchangeably and are not interchangeable. The difference is scope, and it is easiest to see side by side:

What each framework covers
FrameworkAcademicsBehaviourAttendanceOrigin
RTI (Response to Intervention)YesNoNoReading and maths intervention; tied historically to specific learning disability identification
PBIS (Positive Behavioral Interventions and Supports)NoYesIndirectlyBehaviour, school climate and discipline reduction
MTSSYesYesYesAn umbrella that absorbed both, plus social-emotional and attendance

In most districts, MTSS is what you get when RTI and PBIS are run by the same team using one data cycle instead of two. Where the distinction still matters is in special education: RTI's tiered data was written into the process for identifying specific learning disabilities in a way that MTSS as a general framework is not, so the documentation requirements differ. If somebody in your district insists on the difference, that is usually why.

The communication obligation nobody writes down

Almost every district MTSS handbook describes the tiers, the screening calendar and the team structure. Very few state what families are told, when, and by whom — which is why Tier 2 support so often begins without anybody at home knowing it has.

A defensible family-communication cadence by tier
TierTriggerMessageChannel
1Start of year, each screening windowWhat screening happens and how results are sharedUniversal — newsletter, website, one message
2Within one week of support startingWhat support, why, how long, how progress is sharedDirect to guardians, home language, on a channel they use
2Every four to six weeksProgress and whether the plan is changingDirect, brief, consistent
3Before intensive support beginsA meeting, not a notificationPerson to person, interpreter arranged
3Ongoing, at least monthlyProgress against the documented planDirect, with a named contact
ExitWhen a student moves down a tierWhat changed and what continuesDirect

Two design consequences follow. First, these are per-family messages, not broadcasts, so the platform needs to send to specific people reliably and in the right language. Second, the tier-change events are exactly the kind of thing districts want automated — and we will be plain that Kastr's automated-notice rules configure but no engine fires them today. That is roadmap, not product, and anybody selling you tier-triggered automation should be asked to demonstrate it firing on live data.

Attendance is the tier that gets forgotten

Attendance is where MTSS most often exists on paper and not in practice, which is unfortunate because it is the domain where a tiered structure maps most cleanly onto action:

  • Tier 1 is universal: clear attendance expectations, an accurate count, and a message early in the year explaining how absences accumulate. Most families genuinely do not know that two days a month reaches the chronic absenteeism threshold.
  • Tier 2 is a pattern-triggered conversation — a call at the fifth absence, from a person, asking what is making it hard to get to school. Not a letter, and certainly not a legal notice.
  • Tier 3 is case management: a named adult, a plan, and coordination with health, transport or housing services.

Where the tiers break. Tier 2 attendance outreach fails on reachability, not on design. The families whose attendance is worst overlap heavily with the families whose contact data is stale, whose home language is not English, and whose phone number changed in October. A tiered plan that assumes contact works is a plan that fires reliably at exactly the students who need it least.

Questions people actually ask

What is the difference between MTSS and RTI?

RTI is a tiered framework for academic intervention, historically tied to the identification of specific learning disabilities. MTSS is broader: it covers academics, behaviour, attendance and social-emotional support in one structure with one data cycle. In practice, most districts describing MTSS are running RTI and PBIS under one team.

How many students should be in Tier 2 and Tier 3?

The conventional design targets are roughly 10 to 15 per cent in Tier 2 and 3 to 5 per cent in Tier 3. If far more students need Tier 2, the usual diagnosis is that Tier 1 core instruction needs attention rather than that more intervention capacity is needed.

Is MTSS required by federal law?

Not as a named framework. Federal law permits tiered intervention data in the identification of specific learning disabilities and encourages multi-tiered approaches through several funding streams, and many states require MTSS or an equivalent by statute or regulation. Whether it is mandatory for you is a state question.

Does MTSS apply to attendance or only academics?

It applies to attendance, and attendance is often the domain where the tiers map most cleanly onto action. Tier 1 is universal information, Tier 2 is a pattern-triggered conversation with a person, Tier 3 is case management. The limiting factor is nearly always whether the district can actually reach the family.

One price. Every feature. Locked for three years.

$3.50 per student per year under 5,000 students. No tiers, no add-on modules, no per-message fees. Published on the site because you should not have to book a call to learn a price.