Two measures of preference during forced-choice assessments.

The team ran a forced-choice preference assessment. They placed two items on a table. The child could pick one.

They tracked two things. First, which item the child touched. Second, how fast the child touched it. They called the speed "latency."

The goal was to see if latency matched the simple approach score. If they matched, latency could give the same answer faster.

Latency and approach scores pointed to the same favorite items. The faster the child reached, the higher the item ranked.

The authors said latency is a "useful supplemental" measure. It adds no extra steps, just a stopwatch.

Lambert et al. (2017) took the same latency idea into functional analysis. They tested 18 hospitalized kids with autism. Latency cut test time and kept kids safe.

Johnson et al. (2009) also used latency, but to rank demands, not toys. Short latencies showed which tasks triggered problem behavior fastest.

Kahng et al. (1999) compared real items to photos. Real items won. Davison et al. (1995) used real items too, so the two studies agree: keep it tangible.

Next time you run a paired-stimulus preference assessment, start the clock when you say "pick." Stop it when the child touches an item. Write the seconds next to the item name. You get two measures for the price of one. If a child is slow to reach, the item may be less valuable. This tiny add-on costs nothing and can confirm your hierarchy without extra trials.