The Rehabilitation Treatment Specification System: A Missing Link Between Occupational Therapy and Precision Rehabilitation

Rehabilitation has existed for decades, but we still struggle to explain exactly what makes a treatment work.

We can usually describe the activity we completed.

We provided gait training. We worked on cognition. We practiced dressing. We completed strengthening. We addressed balance. We used neuromuscular re-education.

Those descriptions may tell another person what the session looked like, but they do not necessarily identify the part of the treatment that was expected to create change.

• What did the clinician actually do?
• What patient function was directly targeted?
• How much of the treatment was delivered?
• What mechanism did we believe connected the intervention to the change?

Those questions matter because rehabilitation is moving toward greater precision. If we want to match interventions to individual patients, compare treatment responses, replicate successful approaches, and understand why one person improves while another does not, we need to describe treatment more precisely than “the patient received occupational therapy.”

The Rehabilitation Treatment Specification System, commonly called the RTSS, was created to help rehabilitation professionals open this black box.

The Problem With Naming Rehabilitation by Discipline

Rehabilitation interventions are often described according to the profession delivering them or the general problem being treated.

Examples include:

• Occupational therapy
• Physical therapy
• Cognitive rehabilitation
• Balance training
• Gait training - Lower Body for OT Course
• Strengthening
• ADL training - Resource page for ADL/IADL Training
• Patient education - Free Handouts for patient education and clinician guidance

These labels are convenient, but they are not specific enough for science.

Two occupational therapists can both document “ADL training” while delivering completely different interventions.

One therapist may repeatedly practice the physical sequence of dressing.

Another may teach the patient to use a written checklist.

Another may modify the environment.

Another may train the caregiver to provide graded cues.

Another may use errorless learning to establish a routine.

All five interventions could be documented as ADL training, but they do not contain the same treatment ingredients, target the same patient function, or operate through the same mechanism.

The RTSS was developed because classifying treatment by discipline or general activity does not tell us which clinician actions are expected to affect which patient functions.  

What Is the Rehabilitation Treatment Specification System?

The RTSS is a theory-driven framework for describing rehabilitation treatments.

It does not tell the clinician which intervention to choose. It gives the clinician a structured way to explain the intervention that was chosen.

Under the RTSS, a treatment component includes three central parts:

• The target: the patient function the clinician intends to change directly
• The ingredients: what the clinician does or provides to change that target
• The mechanism of action: the known or hypothesized process through which the ingredients affect the target

The target and ingredients should be observable and measurable. The mechanism of action may be measured in research or may remain a reasoned hypothesis in clinical practice.  

This creates a basic causal structure:

The clinician delivers specific ingredients, through a proposed mechanism of action, to create change in a defined treatment target.

That sounds simple, but it requires far more reasoning than naming an activity.

Ingredients Are Not the Same as Activities

An activity is what the patient appears to be doing.

An ingredient is what the clinician intentionally provides.

Imagine that a patient repeatedly practices standing from a chair.

The activity is sit-to-stand.

The ingredients might include:

• Verbal instruction to move the feet backward
• Demonstration of anterior weight shifting
• Tactile guidance at the pelvis
• Reduction of upper-extremity support
• Ten repetitions
• Feedback after each attempt
• Gradual changes in chair height
• Rest intervals based on movement quality

The clinician may believe that these ingredients improve movement through repeated task-specific practice, feedback, motor learning, strength adaptation, or improved anticipatory postural control.

Simply documenting “sit-to-stand training” does not capture that reasoning.

The RTSS asks us to describe what we introduced into the treatment and why we expected it to work.

Targets Are Not the Same as Functional Goals

One of the most useful RTSS distinctions is the difference between a target and an aim.

A target is the function the treatment is expected to change directly.

An aim is the broader outcome expected to improve because the target changed.

For example:

• The target may be the patient’s ability to initiate anterior weight shifting before standing.
• The aim may be completing a toilet transfer independently.

Another example:

• The target may be the patient’s accurate use of a written sequencing strategy.
• The aim may be preparing breakfast safely.

The clinician does not directly insert independence into the patient.

The clinician delivers treatment ingredients intended to modify a specific function. Improvement in that function may then contribute to a broader activity or participation outcome.

RTSS authors describe targets as the direct effects of treatment and aims as downstream or more distal effects.  

This distinction is especially important for occupational therapy.

Occupation may be the ultimate aim of treatment, but reaching that aim may require us to directly target strength, motor planning, sensory discrimination, strategy use, emotional regulation, habit formation, environmental support, or another underlying function.

We should be able to explain the pathway connecting the treatment to occupational performance.

The Three RTSS Treatment Groups

Earlier rehabilitation taxonomy work used four treatment groups, but the formal RTSS consolidated these into three groups of treatment components:

1. Organ Functions
2. Skills and Habits
3. Representations

These groups are based on the type of target being addressed and the mechanisms through which change is expected to occur.  

1. Organ Functions

Organ-function treatments directly target physiological functions.

Examples may include:

• Muscle force
• Joint range
• Cardiovascular endurance
• Pain
• Swallowing physiology
• Muscle tone
• Tissue flexibility
• Respiratory function

The patient does not necessarily need to understand or deliberately learn the biological process producing the change.

For example, progressive resistance may be delivered to increase muscle force. Prolonged positioning may be used to influence tissue length. Electrical stimulation may be applied to elicit a physiological response.

Structural tissue changes are generally represented within this broader organ-function group rather than as a separate fourth group in the current RTSS.

2. Skills and Habits

Skills and habits involve learned performance.

These treatments require practice and depend on processes such as motor learning, feedback, repetition, reinforcement, and habit formation.

Examples include learning to:

• Complete a transfer sequence
• Use an assistive device safely
• Navigate a wheelchair
• Perform a dressing technique
• Use the affected arm during a daily activity
• Scan the environment while walking
• Follow a structured morning routine

The target is not simply whether the patient completed the activity once.

The target may involve accuracy, efficiency, consistency, automaticity, adaptability, or successful performance under specific conditions.

3. Representations

Representations include thoughts, feelings, knowledge, beliefs, intentions, and internal information that support voluntary action.

Examples include:

• Understanding fall-prevention strategies
• Recognizing personal fatigue triggers
• Believing that movement is safe
• Remembering the steps of a task
• Developing an intention to use a strategy
• Recognizing an error
• Understanding a diagnosis
• Regulating fear during mobility

This category matters because education is not one uniform intervention.

Giving information, changing a belief, teaching a problem-solving strategy, and reducing fear may all require different ingredients and mechanisms.

The RTSS also recognizes volition and effort as important elements in many rehabilitation treatments.  

A Practical Occupational Therapy Example

Consider a patient after a stroke who repeatedly forgets to lock the wheelchair before transferring.

A vague treatment description might say:

Transfer training and safety education were completed.

An RTSS-informed description asks us to go deeper.

Possible target

The patient will consistently initiate the wheelchair-locking step before beginning a transfer.

Possible ingredients

• A bright visual cue placed near the wheel lock
• Verbal explanation of the safety risk
• Demonstration of the transfer sequence
• Repeated practice across ten trials
• Immediate feedback following missed steps
• Gradual withdrawal of verbal cues
• Practice in the bathroom and bedroom

Possible mechanisms of action

• Repetition strengthens the transfer sequence.
• The visual cue supports prospective memory.
• Immediate feedback improves error recognition.
• Practice across environments supports generalization.
• Fading cues promotes independent initiation.

Functional aim

The patient will complete toilet and bed transfers safely with reduced caregiver assistance.

This description reveals far more than “transfer training.”

It also makes the intervention easier to teach, document, reproduce, evaluate, and modify.

Why RTSS Matters for Precision Rehabilitation

Precision rehabilitation aims to deliver the right intervention, at the right dose, to the right person, at the right time.

That cannot happen if our interventions remain poorly specified.

Suppose two patients receive “balance training,” but only one improves.

Without better treatment specification, we may not know:

• Whether they received the same ingredients
• Whether the dose was similar
• Whether the same target was addressed
• Whether the assumed mechanism applied to both patients
• Whether one patient needed a different target
• Whether the functional outcome depended on factors the treatment never addressed

RTSS does not create precision rehabilitation by itself.

However, it supplies part of the infrastructure precision rehabilitation requires.

It gives us a way to define the intervention before asking:

• Who responds?
• Under what conditions?
• At what dose?
• Through which mechanism?
• For which target?
• With what functional result?

This is the shift from saying, “This intervention works,” to asking:

Which ingredients work, for which target, through which mechanism, for which person?

That is a much more scientific question.

What RTSS Could Change in Clinical Practice

When clinicians use RTSS thinking, treatment selection becomes more explicit.

Instead of choosing an intervention because it is traditional, familiar, or commonly used for a diagnosis, the therapist must identify the expected pathway of change.

The therapist begins asking:

• What exactly am I trying to change?
• Is that change observable?
• What am I doing to change it?
• What dose am I delivering?
• Why should these ingredients affect this target?
• How will changing this target improve occupational performance?
• What will I change if the patient does not respond?

That does not remove clinical creativity.

It makes clinical creativity explainable.

What RTSS Could Change in Education

Rehabilitation students are often taught intervention techniques before they are taught how to explain the causal reasoning behind them.

They may learn a collection of methods:

• Weight-bearing
• Visual scanning
• Constraint
• Strengthening
• Cueing
• Repetition
• Compensatory training
• Environmental modification

However, the critical question is not whether the student can name the technique.

The critical question is whether the student can explain:

• The intended target
• The active ingredients
• The hypothesized mechanism
• The expected functional aim
• The patient characteristics that may influence response

RTSS offers educators a shared structure for making reasoning visible.

It can also help students understand why two interventions that look similar may operate differently, and why the same intervention may need to be modified for different patients.

What RTSS Could Change in Documentation

Documentation often emphasizes time, activity, assistance level, and billing language.

Those elements matter, but they do not always communicate the skilled reasoning behind treatment.

An RTSS-informed note could make the treatment clearer by identifying:

• The function directly targeted
• The ingredients delivered
• The dose or progression
• The patient’s response
• The intended connection to occupation

This does not mean every clinical note needs to become a research protocol.

It means our language should reveal why skilled therapy was required.

Clearer intervention specification may strengthen communication, support continuity between clinicians, and make treatment progression easier to understand. Claims that RTSS will directly improve reimbursement still need to be tested, but its structure may help clinicians articulate skilled treatment more precisely.

What RTSS Could Change in Research

Rehabilitation research often measures outcomes more carefully than it describes the treatments that produced them.

That creates a serious problem.

A study may report that an intervention improved function but provide too little detail for another clinician or researcher to reproduce what was delivered.

RTSS offers a framework for specifying the active ingredients, targets, doses, and proposed mechanisms of rehabilitation treatments. This can support intervention design, replication, comparison, evidence synthesis, and translation into clinical practice.  

However, RTSS implementation is still developing.

A recent scoping review identified only 71 eligible articles applying RTSS-related concepts between 2014 and 2024 and found variation in the quality and completeness of its use. Reported implementation barriers include complexity, limited training resources, and difficulty developing confidence in applying the system.  

That does not weaken the need for treatment specification.

It shows that the field is still learning how to do it.

RTSS Is a Framework, Not a Finished Science

RTSS should not become another rigid checklist that clinicians are expected to follow without question.

Its value depends on how accurately we identify targets, ingredients, mechanisms, and aims.

A beautifully specified intervention can still be based on an incorrect mechanism.

A clinician may identify the wrong target.

A treatment may be delivered at an insufficient dose.

A mechanism may apply to one patient but not another.

That is exactly why the framework matters.

It makes our assumptions visible enough to test.

RTSS does not prove that our treatment theory is correct. It forces us to state the theory clearly enough that it could eventually be supported, rejected, or refined.

OTD Students, Read This Twice

If you are in an OTD program, this is the moment to raise your expectations.

RTSS represents the direction rehabilitation science needs to continue moving toward:

• Greater precision
• Mechanism-based reasoning
• Observable treatment targets
• Defined intervention ingredients
• Testable treatment theories
• Reproducible clinical methods
• Clear connections to occupational outcomes

Do not be satisfied with learning that an intervention is “good for stroke,” “good for cognition,” or “good for balance.”

Ask:

• What is the active ingredient?
• What is the direct treatment target?
• What mechanism is being proposed?
• What dose is required?
• What patient characteristics may alter the response?
• What functional aim should improve?
• How would we know whether the theory was wrong?

If your faculty cannot immediately answer every question, that does not mean the question is inappropriate.

It means rehabilitation science still has work to do.

Your generation may help build it.

Final Thoughts

Occupational therapy does not lack creativity, compassion, or clinical insight.

What we have often lacked is a consistent scientific language for describing exactly what we do and how we expect it to produce change.

The RTSS offers a way forward.

It helps separate:

• The activity from the active ingredients
• The treatment target from the functional aim
• The clinician’s action from the patient’s response
• The proposed mechanism from the outcome
• The name of a profession from the actual treatment delivered

This matters for clinical care.

It matters for education.

It matters for documentation.

It matters for research.

Most importantly, it matters for precision rehabilitation.

We cannot determine which treatment works best for which person until we can clearly describe what the treatment actually is.

RTSS is not the final answer.

It is part of the scientific infrastructure we need to begin asking better questions.

Continue Learning With Us

Did you find this information helpful? Please share this article with another occupational therapy practitioner, student, educator, or rehabilitation professional who may benefit from it.

Would you like access to the clinical resources discussed throughout this article? Explore our membership options to find the level of support that works best for you.

Looking for a more formal learning and mentorship experience? Learn more about the Functional Cognition Lab Mentorship Program.

You can also explore our AOTA-approved courses and clinical resource packages for additional education, treatment resources, and practical tools you can use in rehabilitation practice.

Interested in receiving free functional cognition education each week? Subscribe to the Functional Cognition Lab Newsletter.

Helpful References

Hart, T., Tsaousides, T., Zanca, J. M., Whyte, J., Packel, A., Ferraro, M., & Dijkers, M. P. (2014). Toward a theory-driven classification of rehabilitation treatments. Archives of physical medicine and rehabilitation, 95(1 Suppl), S33–44.e2. https://doi.org/10.1016/j.apmr.2013.05.032

Hart, T., Dijkers, M. P., Whyte, J., Turkstra, L. S., Zanca, J. M., Packel, A., Van Stan, J. H., Ferraro, M., & Chen, C. (2019). A Theory-Driven System for the Specification of Rehabilitation Treatments. Archives of physical medicine and rehabilitation, 100(1), 172–180. https://doi.org/10.1016/j.apmr.2018.09.109

Van Stan JH, Dijkers MP, Whyte J, Hart T, Turkstra LS, Zanca JM, Chen C. The Rehabilitation Treatment Specification System: Implications for Improvements in Research Design, Reporting, Replication, and Synthesis. Arch Phys Med Rehabil. 2019 Jan;100(1):146-155. doi: 10.1016/j.apmr.2018.09.112. Epub 2018 Sep 27. PMID: 30267666; PMCID: PMC6452635.

Van Stan, J. H., Whyte, J., Duffy, J. R., Barkmeier-Kraemer, J., Doyle, P., Gherson, S., Kelchner, L., Muise, J., Petty, B., Roy, N., Stemple, J., Thibeault, S., & Tolejano, C. J. (2021). Voice Therapy According to the Rehabilitation Treatment Specification System: Expert Consensus Ingredients and Targets. American journal of speech-language pathology, 30(5), 2169–2201. https://doi.org/10.1044/2021_AJSLP-21-00076

Zanca, J. M., Turkstra, L. S., Chen, C., Packel, A., Ferraro, M., Hart, T., Van Stan, J. H., Whyte, J., & Dijkers, M. P. (2019). Advancing Rehabilitation Practice Through Improved Specification of Interventions. Archives of physical medicine and rehabilitation, 100(1), 164–171. https://doi.org/10.1016/j.apmr.2018.09.110