This is a really important question that (while I was still at SC), we spent a lot of time thinking, discussing and, at least for me, worrying about.
As Frannie and Lauren mentioned, it’s possible to set benchmarks at the 25% and 75% level to create three broad categories that generally show that children are able to do almost none, some, or almost all of the IDELA activities correctly. However, this comes with a couple of limitations. First of all, we should be *very* careful comparing domains against each other–25% on Motor does not indicate the same level of development as 25% on Emergent Literacy. Second of all, we need to be very cautious about interpreting the results because they are not age-adjusted–of course younger children are going to be considered “struggling” more often than older kids, even when they may be developmentally very much on track.
Also as Lauren alludes to, the ideal benchmarking situation will consist of (unfortunately) a much more involved process, but also one that will yield much more informative and culturally and policy relevant information. That process, simply stated, involves convening a panel of experts in a given context, reviewing the individual activities that children are asked to do on the assessment, and coming to a consensus of what children would be expected to be able to do at various ages. After deciding on the individual activities, these can be
The biggest advantage of this approach is that it generates conceptually comparable benchmarks for different domains and ages of children–you might find that a score of 50% on Motor would generate worry for a 6-year-old, but that on the Emergent Literacy Domain (which is substantially “harder”) would be considered on-track.
This non-statistical benchmarking approach is generally known as “Policy linking” and there are a variety of approaches that can be used. When done in a systematic way across contexts, it can yield a much more nuanced and informative benchmark.