If your child receives ABA therapy, or if you are an RBT running skill acquisition programs, you have almost certainly seen the abbreviations LD and LRFFC on a treatment plan or a VB-MAPP protocol. They both live under the broader umbrella of listener skills, they are assessed side by side, and they are easy to confuse. They are not the same skill, and the difference matters for how targets are written, how sessions are run, and how progress is read.
This guide covers what the VB-MAPP measures in each area, how listener responding develops into listener responding by function, feature, and class, what these targets look like in a real session, and what practice at home can add. It is written for both audiences we serve: families trying to understand a treatment plan, and RBTs and students preparing to run these programs well.
If you want the home-practice side in more depth, our companion article on listener responding at home stays at the parent level. This one goes further into the assessment itself.
The VB-MAPP in one minute
The Verbal Behavior Milestones Assessment and Placement Program, developed by Dr. Mark Sundberg, is one of the most widely used language assessments in ABA programs for young children. Its core Milestones Assessment contains 170 measurable milestones organized into three developmental levels: Level 1 spans roughly 0 to 18 months of typical language development, Level 2 spans 18 to 30 months, and Level 3 spans 30 to 48 months.
The milestones cover the verbal operants from Skinner's analysis of verbal behavior, mand, tact, echoic, intraverbal, alongside listener skills, imitation, play, social behavior, visual perceptual skills and matching-to-sample, linguistic structure, group skills, and early academics. The full VB-MAPP also includes a Barriers Assessment covering 24 common learning and language barriers and a Transition Assessment with 18 areas that inform placement decisions.
A VB-MAPP is not a diagnosis and not a score to compare children against each other. It is a map: it shows where a child's repertoire sits relative to typical language development and tells the BCBA where intervention should start.
Listener responding: understanding before speaking
Listener responding, abbreviated LD in the VB-MAPP, is the receptive side of language: what a child can understand and act on, separate from what the child can say. When an adult says touch your nose and the child touches their nose, that is listener responding, even if the child cannot yet say the word nose.
Early listener responding milestones involve attending to a speaker's voice, responding to their own name, and following simple instructions in context. Later milestones involve following instructions out of context, identifying named items and pictures from an array, and following multi-step directions. Listener skills are assessed across all three VB-MAPP levels because they develop across that entire span.
Listener responding matters clinically because it usually runs ahead of expressive language and because so much of daily life, safety instructions included, depends on it. A child who reliably responds to stop, come here, and give me is safer and more independent than raw vocabulary counts suggest.
LRFFC: listener responding by function, feature, and class
Listener responding by function, feature, and class, abbreviated LRFFC, is the more advanced skill, and it appears in Levels 2 and 3 of the VB-MAPP. In plain LD, the child finds the item that was named: touch the apple. In LRFFC, the item is never named. The child must find it from a description of what it does, what it has, or what group it belongs to.
Function: touch the one you eat, and the child selects the apple. Feature: touch the one with wings, and the child selects the airplane. Class: touch the one that is an animal, and the child selects the dog. The child hears language about the item rather than the item's name, and has to bridge that gap.
That bridge is why LRFFC is such a heavily targeted area. It requires the child to relate words to other words, not just words to objects, and it is one of the stepping stones between simple labeling and conversational language. A child who can answer touch the one you drink from is building exactly the repertoire that later supports answering what do you drink from? in conversation, an intraverbal skill.
What LRFFC targets look like in a session
A typical LRFFC program presents an array of pictures or objects, the RBT delivers the instruction, find the one that..., and the child responds by touching, pointing, or handing over the correct item. Programs usually begin with strong contrasting arrays and well-known items, then systematically increase array size, rotate targets, and mix function, feature, and class statements for the same item.
For RBTs, three quality markers separate a well-run LRFFC program from a mechanical one. First, vary your carrier phrases: if every trial starts with find the one, the child may learn the routine rather than the language, so alternate among find, touch, show me, give me, where is. Second, rotate materials and arrays so the child responds to the description, not to a memorized card position. Third, capture the skill in the natural environment: at snack time, which one do you drink from is an LRFFC trial that costs nothing and generalizes everything.
Data on these programs typically track correct independent responses per target, and your BCBA will specify mastery criteria in the plan. If you are unsure whether a response should be counted when the child self-corrects, ask the BCBA rather than guessing: consistent data definitions across a team matter more than any single session's numbers.
How parents can support both skills at home
Everyday routines are full of natural listener trials. During bath time, wash your belly is listener responding; hand me the one you squeeze is LRFFC. In the kitchen, get the cereal is LD; get the one we pour milk on is LRFFC. The rule of thumb: name the item for early learners, describe the item for children working on LRFFC, and keep it playful rather than drilling.
Follow your child's program rather than running ahead of it. If your BCBA has LRFFC targets in acquisition, ask which items are current and which carrier phrases the team is using, so home practice strengthens the same repertoire instead of muddying the data. And celebrate the receptive wins: a child who followed a new two-step instruction did something as significant as saying a new word, even though it is quieter.
For a fuller set of home strategies, see our guide on helping with listener responding at home.
Where to go deeper
The authoritative source on the VB-MAPP is Dr. Sundberg's own publication and the protocol itself; the official VB-MAPP page describes the full five-component structure. Your child's BCBA can walk you through the completed milestones grid, which is genuinely readable once someone shows you how the levels and skill areas are laid out.
If you are an RBT or an aspiring one, LRFFC programs are a core part of the skill acquisition work covered in training. Our 40-hour RBT training covers discrete-trial teaching, naturalistic teaching, and the listener skill programs discussed here, in English and Spanish.
