Table 6.

Classification table and measures for analysis.

Pretreatment test score	Treatment outcome
	Did not respond to treatment (−)	Did respond to treatment (+)
At or above the criterion score (predicted to respond to treatment; +)	False positive	True positive
Below the criterion score (predicted to not respond to treatment; −)	True negative	False negative

Note. Treatment outcome criteria = five or more treated words with correct definitions. Accuracy = (true positive + true negative)/total. Sensitivity = true positive/(true positive + false negative); probability that the score on the pretreatment measure predicts a child will respond to the treatment when the child actually did respond to treatment (> 80% is desirable). Specificity = true negative/(true negative + false positive); probability that the score on the pretreatment measure predicts a child will not respond to the treatment when the child actually does not respond to treatment (> 80% is desirable). Positive likelihood ratio = true positive/false positive; indicates how likely a child is to respond to treatment as opposed to not respond to treatment given a pretreatment score at or above the cut-off (≥ 3.0 is suggestive, ≥ 10.0 is informative).

Negative likelihood ratio = false negative/true negative; indicates how likely a child is to respond to treatment rather than not respond to treatment given a pretreatment score below the cut-off (≤ 0.30 is suggestive, ≤ 0.10 is informative). See https://www.medcalc.org/calc/diagnostic_test.php for a program to calculate these measures.