Use of NON-PARAMETRIC Item Response Theory to develop a shortened version of the Positive and Negative Syndrome Scale (PANSS)

Table 7 Slopes, Item Biserial Correlation for the Negative Symptoms subscale

Items	Slopes	Rank of Slopes	Item biserial correlation
N6. Lack of spontaneity and Flow of conversation	0.461	1	0.796
N1. Blunted Affect	0.447	2	0.771
N2. Emotional Withdrawal	0.447	3	0.809
N4. Passive Apathetic Social Withdrawal	0.447	4	0.773
N3. Poor Rapport	0.401	5	0.796
N5. Difficulty in Abstract Thinking	0.401	6	0.599
N7. Stereotyped Thinking	0.372	7	0.596

Note. Slopes were extracted from TestGraf output and were rounded to three decimal
places. Similarities in the values of slopes are due to rounding (e.g. slope of N1 is
0.447427, slope of N2 is 0.447313, slope of N4 is 0.447182, slope of N3 is 0.400801, and slope for N5 is 0.400560).

ISSN: 1471-244X