How much change is true change? The smallest detectable difference of the Preschool Imitation and Praxis Scale (PIPS) in preschoolers with intellectual disabilities of heterogeneous aetiology.
A 7% jump on the PIPS is the smallest real gain you can trust when tracking imitation in preschoolers with ID.
01Research in Context
What this study did
The team asked: how big does a PIPS score jump have to be before we call it real?
They gave the Preschool Imitation and Praxis Scale twice to preschoolers with Down syndrome, autism, or other intellectual disabilities.
High inter-rater reliability was shown, then they used a formula to find the smallest detectable difference.
What they found
A change of 7.2% on the PIPS is the smallest gain you can trust.
Anything smaller is probably just measurement noise, not true growth in imitation skills.
How this fits with other research
Whitaker (2008) saw that IQ scores usually stay put in people with low ability, yet about 1 in 7 shift 10+ points over three years.
That big-picture stability matches the tiny 7% noise band found here; both warn you to expect only small wobble unless real change hits.
Burrows et al. (2018) showed SIS-A adult scores stay flat for 1–3 years and flagged the medical/behavioral sections as the spots that truly move.
Together these papers give you a rule set: preschool imitation needs 7%, adult support needs section-level review, and IQ needs a 10-point eye before you call it change.
Why it matters
Next time you re-test imitation after teaching gestures or toy play, look for at least a 7% jump on the PIPS. Smaller bumps are likely noise, so keep the intervention running and save celebration for the real deal.
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Join Free →After each PIPS re-test, subtract the old score from the new; if the change is under 7%, keep teaching instead of writing a new goal.
02At a glance
03Original abstract
The teaching of imitation skills is often the first step in interventions for young learners with intellectual disabilities. The main goal of this study was to determine the smallest detectable difference (SDD) at 95% confidence of the Preschool Imitation and Praxis Scale (PIPS) in preschoolers with intellectual disabilities. Two raters independently scored videotapes of the imitation performance of 44 preschoolers (27 with Down syndrome, 10 with Non-Specific Mental Retardation and 7 with Low-functioning Autism) between 13 and 58 months of age (mean age 39.6 months, SD 11.9 months). Results revealed that the PIPS demonstrated acceptable interrater reliability on item level (weighted kappa values ranged from 0.52 to 0.96) and scale level (ICC = 0.986; 95% CI: 0.975-0.993). The SDD of the PIPS was 7.2%, indicating that the change score rated by different raters for an individual child with an intellectual disability is valid and that the PIPS can be used by early interventionists and researchers as an outcome measure to determine children's maturation or improvement.
Research in developmental disabilities, 2011 · doi:10.1016/j.ridd.2010.09.019