PECS vs AAC: What's the Difference?
The two terms get used almost interchangeably in casual conversation, but they are not the same thing, and understanding the relationship between them makes choosing an approach far less confusing.
PECS is one specific type of AAC, not a separate category from it. AAC is the umbrella term for any tool that supports or replaces speech, and PECS, a structured picture-exchange system, sits alongside speech-generating devices and other picture-based systems as one option within it. A meta-analysis found that for preschoolers, both PECS and speech-generating devices were significantly more effective than other picture-based approaches, with no clear overall winner between the two.
PECS Is a Type of AAC, Not a Rival to It
AAC is the umbrella category, any tool that supports or replaces spoken communication. PECS, the Picture Exchange Communication System, is one specific, structured approach within that category, built around physically exchanging a picture card for a desired item across a series of defined phases. Speech-generating devices are a different specific approach within the same category. Asking "PECS or AAC" is a bit like asking "an apple or a fruit," the comparison that actually matters is PECS against other specific AAC options, most often speech-generating devices.
What the Research Found
A meta-analysis by Ganz and colleagues, published in the American Journal on Intellectual and Developmental Disabilities, investigated how individual characteristics and AAC type interacted across a large body of single-case research on individuals with autism. For preschool-aged children specifically, both PECS and speech-generating devices produced significantly stronger effects than other picture-based AAC approaches, with the study noting no clear, consistent advantage of one over the other across outcome measures.
Side-by-Side Comparison
| Feature | PECS | Speech-Generating Device |
|---|---|---|
| Technology needed | None, physical cards only | A device or tablet with software |
| Output | Visual exchange, no spoken sound | Actual spoken words |
| Starting cost | Low | Higher, though basic apps reduce this |
| Teaching structure | Defined, sequential phases | More flexible, varies by device and program |
| Vocabulary size | Limited by physical cards carried | Much larger, easily expandable |
| Best-studied age range | Strong preschool evidence | Strong preschool evidence |
How to Decide
Consider starting with PECS if
You want a low-cost, no-technology entry point with a clear, well-documented teaching sequence to follow.
Consider a speech-generating device if
Your child needs a larger vocabulary than physical cards can practically provide, or benefits from hearing actual spoken output.
Consider using both
Many families use PECS for simplicity on the go and a device for broader vocabulary at home, rather than treating it as an either-or choice.
Frequently Asked Questions
Is PECS a type of AAC?
Yes, PECS (the Picture Exchange Communication System) is one specific type of AAC. AAC is the broader category covering any tool that supports or replaces speech, and PECS, speech-generating devices, and other picture-based systems are all specific approaches within it.
Which is more effective, PECS or a speech-generating device?
A meta-analysis published in the American Journal on Intellectual and Developmental Disabilities found that for preschool-aged children, both PECS and speech-generating devices were significantly more effective than other picture-based AAC approaches, with no clear overall winner between the two.
What exactly is PECS?
PECS is a structured, phase-based system where a child physically exchanges a picture card for a desired item, starting with simple single-picture exchanges and building toward sentence construction and commenting over successive phases.
Do I have to choose only one system?
No. Many children use PECS as a starting system and transition to or add a speech-generating device later, and some use both in different contexts, PECS for on-the-go simplicity, a device for broader vocabulary at home.
Why might PECS be a good starting point?
PECS requires no technology, is inexpensive to start, and has a clear, well-documented step-by-step teaching sequence, making it accessible for families and educators to begin without specialized equipment or training.
Why might a speech-generating device be a better fit?
A device offers a much larger vocabulary than a practical set of physical picture cards, and produces actual spoken output, which some children and communication partners find more immediately understandable in everyday settings.
Does age affect which system works better?
The same meta-analysis found that age moderated effectiveness, with PECS and speech-generating devices showing their strongest, most consistent effects specifically within the preschool age range, though both remain used successfully with older children as well.
Can switching from PECS to a device cause setbacks?
Not typically, since the underlying communication concept, exchanging a symbol for a want, transfers between systems. Many children move from PECS to a device without losing the communication skills already built, and some professionals recommend PECS specifically as a stepping stone toward device use.
Not sure whether PECS or a device fits your child?
Our free tool helps you build a support profile in a few minutes, a useful starting point before choosing a system.
Free Sensory Profile & Support Tool for Parents →Sources: DSM-5, WHO ICD-11, Ganz, Mason, Goodwyn, Boles, Heath & Davis (2014), American Journal on Intellectual and Developmental Disabilities, 119(6), 516-535, Action for Autism India.