Concurrent, Multiple, Mixed, and Chained Schedules of Reinforcement: A Clinician’s Guide to Distinguishing and Using Schedule Types
If you’re a BCBA, clinic director, or supervisor, you’ve likely encountered situations where getting the schedule type wrong meant the difference between a treatment that worked and one that quietly failed. Maybe you set up what you thought was a straightforward choice scenario, only to realize the behavior wasn’t changing the way you expected. Or perhaps you documented a schedule in a behavior plan, and another clinician interpreted it differently—leading to inconsistent implementation and missed progress.
The root issue is simpler than it might seem: concurrent, multiple, mixed, and chained schedules of reinforcement each work differently, teach different things, and require different measurement strategies. Confusing one for another doesn’t just muddy your data—it can prolong treatment, obscure real progress, and compromise your ability to make informed decisions.
This article walks you through each schedule type in plain language, shows you how to tell them apart, and connects each to real clinical decisions.
What Is a Schedule of Reinforcement, and Why Does the Type Matter?
A schedule of reinforcement specifies when and how often a behavior is followed by a consequence. It answers the question: “Under what conditions will this behavior get reinforced?”
Schedules fall into two broad families. Continuous reinforcement (CRF) means every occurrence of the behavior is reinforced—straightforward but rarely used in clinical work. Intermittent reinforcement means only some occurrences are reinforced, often in patterns like fixed ratio (FR), variable ratio (VR), fixed interval (FI), or variable interval (VI). These patterns create different effects on motivation, persistence, and output.
Within intermittent reinforcement, there’s another layer: how those patterns are arranged. Are they happening at the same time? Alternating? Sequenced? And are there cues telling the learner which rule is in effect? These questions lead us to concurrent, multiple, mixed, and chained schedules.
The schedule you choose determines what you can measure, how you interpret data, and whether behavior will transfer or persist when treatment ends. A schedule perfect for measuring preference won’t teach a skill. A schedule that builds stimulus control looks nothing like one designed for complex sequences. Getting it right means cleaner data, more reliable progress, and ethical implementation.
Concurrent Schedules: When Two or More Options Are Available at the Same Time
A concurrent schedule places two or more reinforcement contingencies side by side, letting the learner choose between them.
Picture this: A child sits at a table with two activities available right now. Pressing a button on a toy music player produces 5 seconds of music. Completing a simple puzzle produces 30 seconds of screen time. Both options are accessible, and the child can choose which one to engage with at any moment. That’s a concurrent schedule.
The key feature is simultaneous availability. The learner’s behavior naturally allocates toward whichever option seems more valuable. By watching where the child directs effort, you can measure response allocation—which option gets more responses, more time, more attempts. That allocation tells you something real about reinforcer preference and relative value. This is why concurrent schedules are workhorses in preference assessment and choice research.
In clinical practice, concurrent schedules help answer questions like: “Which reinforcer is actually stronger for this client?” or “If I offer two competing activities, which will the learner choose?” You can also use them therapeutically—if a learner spends all their time with one reinforcer and ignores skill-building, you might adjust the schedule to shift allocation.
The strength of concurrent schedules is their transparency: the choice is visible, measurable, and real. The caution is that they measure current preference, not necessarily what’s best for the client long-term.
Multiple Schedules: Alternating Components with Clear Signals
A multiple schedule arranges two or more different reinforcement schedules that alternate across time, with each marked by a distinct discriminative stimulus (SD).
An SD is simply a cue that tells the learner, “This rule is in effect right now.” It might be a colored card, a verbal instruction, a location, a timer sound, or any stimulus that consistently appears with a particular contingency.
Here’s a realistic example: A teacher uses a green card to signal a period when earning tokens for on-task behavior is active (FR 5—earn a token for every 5 minutes of work). Then she switches to a red card signaling a period when no reinforcement is available (extinction). These components alternate throughout the day. The green and red cards are the SDs; they tell the student which rule is currently in effect.
The defining feature is the presence of these signals. Because the student can see the green card and knows tokens are available, they can adjust behavior accordingly. If the red card goes up, they learn the contingency has changed. Over time, behavior comes under stimulus control—responding reliably increases with the green card and decreases with the red card. The cue tells them the rule.
Multiple schedules are especially useful when you want to test whether a discriminative stimulus actually controls behavior, or when teaching a client to switch between different rules in different contexts.
Mixed Schedules: Alternating Components Without Signals
A mixed schedule looks like a multiple schedule on paper—two or more schedules alternating across time. But here’s the critical difference: there is no discriminative stimulus. The learner cannot tell which schedule is in effect until reinforcement actually happens.
Imagine the teacher removes the colored cards. Now tokens are available during some periods and not others, but the student has no cue about when shifts occur. The schedule alternates, but the student must figure out what’s happening through trial and error—or through the pattern of reinforcement itself.
Mixed schedules are rarely used in routine clinical practice. They’re typically used in research settings to test whether a stimulus truly controls behavior. The logic: If behavior changes only when the SD is present (multiple schedule), that proves stimulus control. If you remove the SD and behavior still changes the same way (mixed schedule), something else might be controlling it—perhaps schedule pattern, history, or other environmental cues.
Mixed schedules can be unsettling for learners because the rules are unpredictable. Ethical practice requires careful consideration of the client’s ability to tolerate uncertainty and clear documentation of the rationale.
Chained Schedules: Building Sequences One Step at a Time
A chained schedule is fundamentally different from the three schedules above. Instead of presenting choices or alternating rules, a chained schedule requires a sequence of responses in order. The learner cannot skip ahead or go backward; they must complete each component in sequence—and only after completing the entire chain does the final reinforcer appear.
Each component has its own reinforcement rule, and often its own SD to signal which step is active. Critically, primary reinforcement is delivered only after the final component. This is called the terminal reinforcer.
A concrete example: Teaching a child to wash hands before eating. The chain might look like this. First, the child receives a card with a picture of hands (SD for step 1), and they must wash hands for 20 seconds (FR schedule). Completing this produces a second card (SD for step 2). Now they must dry hands on a towel (another FR schedule). Completing step 2 produces a final card (SD for step 3). Now they sit at the table. After all three steps are completed in order, they get access to the snack (terminal reinforcer).
Why use a chained schedule? Because real life is sequential. Getting dressed isn’t a choice between socks or shoes; it’s a sequence where order matters. Chained schedules teach exactly that: completion of a multi-step skill where the learner sees what comes next and receives feedback from moving forward, but the real payoff comes at the end.
The challenge is ensuring each component is teachable and the learner doesn’t give up before reaching the terminal reinforcer. If the chain is too long or difficult, the client may fail repeatedly and lose motivation. Ethical use means breaking chains into appropriate steps, reinforcing progress, and ensuring dignity throughout.
How to Tell These Schedules Apart in Your Daily Work
The best way to distinguish these four schedule types is to ask yourself a series of simple questions:
Are multiple options available at the same time right now? If yes, you’re likely looking at a concurrent schedule. The learner chooses, and their allocation shows preference.
Are different schedules alternating across time with clear cues for each? If yes, it’s a multiple schedule. The SDs are the giveaway—they signal which rule is in effect.
Are different schedules alternating but with no signals? If yes, it’s a mixed schedule. The learner figures out the pattern through reinforcement history alone.
Is there a required sequence of steps, with reinforcement only at the end? If yes, it’s a chained schedule. Each step leads to the next, and the payoff comes after all steps are complete.
When designing treatment, documenting a plan, or reviewing someone else’s work, you should be able to describe the schedule clearly: “We’re using a concurrent schedule with toys A and B to measure preference,” or “This is a multiple schedule with a green light SD for tokens and a red light SD for extinction.”
Common Mix-Ups and How to Avoid Them
The most frequent confusion happens between multiple and mixed schedules. Both alternate different contingencies over time. The difference—the presence or absence of discriminative stimuli—can seem subtle until you realize it changes everything about what the client can learn. A multiple schedule teaches discrimination; a mixed schedule tests whether discrimination is really happening.
Another frequent mistake is treating a chained schedule like a concurrent schedule. This happens when clinicians present a sequence but allow the client to skip steps or choose which step to do first. That’s no longer a chain; it’s a choice scenario requiring different measurement and interpretation.
Clinicians also sometimes assume concurrent schedules always produce stable, predictable choices. In reality, response allocation can shift based on small changes to schedule parameters. Understanding this helps you interpret preference assessments accurately and avoid over-interpreting a single snapshot.
When to Use Each Schedule Type
Start with your treatment goal. What are you trying to accomplish?
Measuring preference or choice behavior? Use a concurrent schedule. Place options side by side, observe allocation, and interpret data as a direct measure of relative value.
Teaching stimulus control or discrimination? Use a multiple schedule. Create clear, distinct SDs for each contingency, and measure whether behavior changes reliably with the stimulus.
Testing whether stimulus control is really happening? Use a mixed schedule as a control condition. Remove the SDs and see if behavior persists, shifts, or disappears.
Teaching a multi-step skill or routine? Use a chained schedule. Break the skill into steps, signal each step clearly, practice the sequence, and deliver the terminal reinforcer at the end.
The schedule choice directly affects data collection. In a concurrent schedule, you measure response allocation percentages. In a multiple schedule, you measure behavior rates or accuracy within each component. In a chained schedule, you measure completion rate and step accuracy. Matching schedule to goal ensures meaningful data.
Real-World Examples
Concurrent schedule in practice: You’re running a preference assessment for a client with autism who communicates minimally. You place a toy, a snack, a book, and a sensory item on a table simultaneously. Over 10 minutes, you track which item the client reaches for most. That allocation tells you which reinforcer is strongest. You can use this information to shape communication or reward compliance.
Multiple schedule in practice: A classroom uses a token economy where a green light signals “tokens are available for raising your hand and waiting your turn.” A red light signals “no tokens right now; this is individual work time.” Students learn to increase hand-raising under green and reduce it under red. The behavior is under stimulus control, and students can adapt to context.
Mixed schedule in practice: A therapist alternates reinforcement schedules (sometimes FR 5, sometimes VR 5) during a session without announcing changes. The client’s responding may vary based on reinforcement history, but without explicit signals, the client cannot predict which schedule is in effect. This is typically a research design rather than treatment, revealing whether the client relies on external cues or learned patterns.
Chained schedule in practice: Teaching a child to get dressed. Step 1 (SD: blue card): Put on socks (FR). Step 2 (SD: green card): Put on shoes (FR). Step 3 (SD: yellow card): Buckle shoes (FR). Step 4 (SD: red card): Go to breakfast (FR). Terminal reinforcer: Eat breakfast. Each completed step signals the next and builds momentum.
Ethical Considerations: Dignity, Clarity, and Consent
The choice of schedule has ethical implications beyond data collection. Unsignaled (mixed) schedules can create confusion and frustration, especially for learners with limited ability to detect patterns or tolerate unpredictability. Using an unsignaled schedule clinically requires clear justification, informed consent where applicable, and careful monitoring for distress.
Chained schedules, while powerful teaching tools, can also create frustration if steps are too difficult or too long. A chain requiring 20 steps before any reinforcement may feel punitive, even if intended otherwise. Ethical practice means building in intermediate rewards, breaking chains into teachable units, and ensuring the client experiences success and dignity throughout.
Clear documentation and supervision are non-negotiable. Your behavior plan should specify which schedule type you’re using, which SDs are involved, and why you chose that schedule for this client. When a supervisor reviews the plan, they should immediately understand your intent. This clarity prevents misimplementation and supports consistent care.
Finally, consider cultural and contextual fit. Some families or settings have preferred ways of organizing tasks or rewards. A chained schedule that disrupts family routines or contradicts cultural values may be less effective and ethically questionable, even if technically sound. Adapt respectfully and collaboratively.
Quick Comparison: At a Glance
Here’s what sets these four schedules apart:
- Concurrent: Multiple options available right now. Learner chooses. Measures preference.
- Multiple: Schedules alternate over time. Each has a clear signal (SD). Teaches discrimination.
- Mixed: Schedules alternate over time. No signals. Tests stimulus control.
- Chained: Schedules in a fixed sequence. Each step leads to the next. Terminal reinforcer at the end. Teaches multi-step tasks.
Key Takeaways
Identifying and distinguishing among concurrent, multiple, mixed, and chained schedules is foundational to accurate assessment, effective treatment design, and ethical practice. Each schedule type answers a different clinical question and produces different outcomes.
Concurrent schedules show you what the learner values most. Multiple schedules teach discrimination between cues and contexts. Mixed schedules help verify stimulus control in research. Chained schedules build complex, sequenced skills.
Getting the schedule type right affects everything downstream: what you measure, how you interpret data, whether treatment works, and whether the learner experiences dignity and success. When uncertain, pause and ask those simple questions: Are options simultaneous or alternating? Are there signals or not? Is there a required sequence? Your answer points directly to the schedule you’re using.
As you review your current cases, consider revisiting the schedules you’ve designed. Are they clearly documented? Do they match your treatment goals? Would a colleague reading your plan immediately understand which schedule you’re using and why? That clarity transforms good intentions into reliable, ethical, and effective treatment.
