Table 4.

Table for Converting Summed Scores to Item Response Theory (IRT)–Scaled T-Scores for the University of North Carolina Genomic Knowledge Scale (UNC-GKS)

	25-Item UNC-GKS		19-Item UNC-GKS
Summed Score	T-Score	Standard Error	T-Score	Standard Error
0	21.7	5.0	21.9	5.1
1	24.3	4.6	24.6	4.7
2	26.7	4.2	27.1	4.3
3	28.8	3.8	29.4	4.0
4	30.6	3.5	31.4	3.8
5	32.2	3.2	33.3	3.6
6	33.7	3.0	35.1	3.5
7	35.0	2.8	36.8	3.5
8	36.2	2.7	38.4	3.5
9	37.3	2.6	40.1	3.5
10	38.4	2.5	41.8	3.6
11	39.5	2.4	43.5	3.7
12	40.6	2.4	45.4	3.8
13	41.6	2.4	47.3	4.0
14	42.7	2.5	49.4	4.2
15	43.9	2.6	51.8	4.5
16	45.1	2.7	54.4	4.9
17	46.3	2.9	57.4	5.4
18	47.7	3.1	61.0	5.9
19	49.3	3.4	65.0	6.5
20	51.1	3.7
21	53.1	4.1
22	55.5	4.5
23	58.2	5.1
24	61.6	5.7
25	65.4	6.3

Note: This table can be used to convert the summed count of a participant’s correct responses (summed scores) to item response theory scaled scores in the T-score metric, allowing easy comparison across studies and populations. These T-scores were calculated using this study’s sample, a population mean of 50, and standard deviation of 10. To convert a score, find a participant’s summed score in column 1 and follow the row to determine the IRT-scaled T-score and standard error for the 25- and 19-item versions of the UNC-GKS.