Examining Sensitivity to Developmental Changes on the Behavioral Inflexibility Scale.

A Boyd et al. (2024) asked a simple question: does the Behavioral Inflexibility Scale (BIS) notice real growth in autistic kids?

Parents filled out the 16-item BIS twice, one year apart. No extra teaching or drugs were given.

The team then checked if the scores moved enough to say, "Yes, this child is more flexible now."

Scores did shift. The BIS caught developmental change over twelve months.

That means the tool is sensitive, not stuck on the first number it sees.

Harrop et al. (2024) used the same scale and showed BIS numbers forecast anxiety better than age, IQ, or label. Brian’s team adds, "And those numbers also move as kids grow."

Fecteau et al. (2003) first showed core autism traits can ease with time. Brian’s work zooms in on one trait—inflexibility—and gives us a ruler to watch it change.

Strang et al. (2017) built a different parent scale called the Flexibility Scale. Both tools chase the same skill, so you can pick either; just stay consistent.

You now have a free, quick parent form that tracks real-world rigidity over months. Use it at intake, then again every six to twelve months. If the score drops, celebrate and keep the plan. If it stalls, teach flexibility skills or probe for hidden anxiety. One page, one number, clear direction.