Skip to main content
. Author manuscript; available in PMC: 2012 Oct 9.
Published in final edited form as: School Psych Rev. 2012 Fall;41(1):3–22.

Table 2.

Cross Tabulation of Latent and Observed Classifications When the Ignorable Difference is .25 and Important Difference is 1.0 for the Concordance-Discordance Method

Latent Classification
Observed
Classification		 Not SLD Frequency
(%)		 SLD Frequency
(%)		 Total Frequency
(%)
Not SLD 185,574 (83.86%) 1246 (.56%) 186,820 (84.42%)
SLD   26,334 (11.90%) 8131 (3.67%)   34,465 (15.57%)
Total 211,908 (95.76%) 9377 (4.24%) 221,285 (100%)

Note. 221,285 cases remained after applying achievement (<90) and mental ability (>69) cutoffs to a population of 1,000,000. Observed classification as SLD required specific pattern of 2 significant differences and one nonsignificant difference among two cognitive variables and one achievement variable. Latent classification required specific pattern of two differences larger than 1.0 and one difference no larger in an absolute sense than .25. Cases not meeting these criteria were classified as Not SLD. For this definition, Sensitivity = .87, Specificity = .88, PPV = .24, NPV = .99, and base rate = 4.24%.