Comparison of visual analysis, non-overlap methods, and effect sizes in the evaluation of parent implemented functional assessment based interventions.

Barton et al. (2019) looked at 40 parent-run functional assessment studies. They checked how often authors used the same visual-analysis words. They also compared expert graph reading to two number scores: NAP and Tau-U.

The same graph features were called by many different names. Experts and the NAP/Tau-U numbers often disagreed on whether a change was big. The newer BC-SMD score still needs more proof.

Manolov et al. (2014) already told us to add trend lines and split-middle numbers to graphs. E et al. show that, even with those tips, labels stay messy and numbers still clash with eyeball tests.

Azim et al. (2025) move past single-diagnosis FA. They group kids by shared traits like poor sleep or talk delays. Their wider lens may shrink the label chaos that E et al. found.

Matson et al. (2011) found most FA work uses tiny samples of boys with ID/ASD. E et al. kept seeing the same small, narrow groups, so the disagreement problem hits the same kids again and again.

Before you send a graph to a parent, school, or journal, pick one label set and stick to it. Add a trend line and write the NAP or Tau-U under the graph. Tell the reader which word means “big change” and which means “small.” This small step can cut reviewer fights and helps parents trust the data.