Dog training glossary
Fixed Ratio / Variable Ratio Reinforcement
Quick answer
Two ways of scheduling rewards by number of responses: a fixed ratio rewards every set number of correct repetitions, a variable ratio rewards after an unpredictable number.
Written by the TailorPup team, updated September 2026. See our editorial approach.
What it means
A fixed ratio (reward every third correct sit, for example) is predictable and useful early on, but a dog can learn to anticipate exactly when the reward is coming and slack off in between. A variable ratio, rewarding after an unpredictable number of repetitions, tends to produce more persistent, harder-to-extinguish behavior, the same principle that makes slot machines compelling, and is typically introduced only once a behavior is already well established.
A real example
A dog trained with a fixed ratio might get a treat every third "sit" reliably; the same dog moved to a variable ratio might get rewarded after the first sit, then not until the fifth, keeping it consistently engaged since it can't predict which repetition pays off.
A worked example
Theo's dog sits for every treat. Later he asks for two sits per treat (fixed ratio), then sometimes one, sometimes four (variable ratio). The dog works faster and more eagerly, because the next one could be the one that pays.
Signs it is working
- The dog works steadily without pauses.
- It keeps going when a reward is skipped.
- It does not drop out as you thin rewards.
What it is not
A ratio schedule is based on counting responses, while an interval schedule is based on time. They produce different patterns.
Common mistake
Switching to a variable ratio schedule too early, before the behavior is fluent, which can cause it to weaken instead of becoming more resistant to fading.
Why it matters
Variable schedules make behaviors resilient, while fixed ones make training predictable. Choosing the right one for each stage saves time.
How to use it
- Use a continuous schedule, reward every time, while the dog is learning.
- Move to a fixed ratio, for instance every second repetition, once the behavior is reliable.
- Switch to a variable ratio by rewarding on an unpredictable pattern.
- If performance drops, step back to a denser schedule.
Which ratio is best?
Variable ratios generally produce the most persistent behavior, which is why slot machines work. For dogs, they are best introduced after the behavior is already well learned.
Related terms
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