Item response analysis of the Positive and Negative Syndrome Scale

BMC Psychiatry

Table 1 Discrimination Effectiveness for the PANSS Items

Item	Content	Summary Evaluation	3 Factor Subscales	Criterion A	Criterion B	Criterion C	Criterion D
1.	Delusions	Very good	Positive	6	Yes	Yes	Yes
2.	Conceptual Disorganization	Very good	Positive	6	Yes	Yes	Yes
3.	Hallucinatory Behavior	Very good	Positive	4	Some	Yes	Yes
4.	Excitement	Good	Positive	6	Yes	Yes	No
5.	Grandiosity	Good	Positive	4	Some	Yes	Yes
6.	Suspiciousness/Persecution	Very good	Positive	6	Yes	Yes	Yes
7.	Hostility	Poor	Positive	6	Yes	Yes	No
8.	Blunted Affect	Very good	Negative	6	Yes	Yes	Yes
9.	Emotional Withdrawal	Very good	Negative	7	Yes	Yes	Yes
10.	Poor Rapport	Good	Negative	6	Yes	Yes	Yes
11.	Passive Apathetic Social Withdrawal	Very good	Negative	7	Yes	Yes	Yes
12.	Difficulty in Abstract Thinking	Poor	Negative	6	Some	Some	Yes
13.	Lack of Spontaneity Conversation	Very good	Negative	6	Yes	Yes	Yes
14.	Stereotyped Thinking	Poor	Negative	6	No	Some	Yes
15.	Somatic Concern	Poor	General	4	No	Some	No
16.	Anxiety	Good	General	5	Yes	Yes	No
17.	Guilt Feelings	Good	General	5	Some	Yes	No
18.	Tension	Good	General	5	No	Yes	Yes
19.	Mannerisms and Posturing	Poor	General	6	Some	Yes	Yes
20.	Depression	Poor	General	5	Yes	Yes	No
21.	Motor Retardation	Good	General	5	Yes	Yes	No
22.	Uncooperative	Good	General	6	Yes	Yes	No
23.	Unusual Thought Content	Poor	General	6	Yes	Yes	No
24.	Disorientation	Poor	General	4	No	No	No
25.	Poor Attention	Poor	General	5	Yes	Yes	Yes
26.	Lack of Judgment and Insight	Poor	General	5	Some	Some	Yes
27.	Disturbance of Volition	Poor	General	6	Yes	Yes	Yes
28.	Poor Impulse Control	Good	General	6	Yes	Yes	No
29.	Preoccupation	Poor	General	5	Some	No	Yes
30.	Active Social Avoidance	Very good	General	6	Yes	Yes	Yes

Criterion A: Number of options for which there was some range of symptom severity in which the question was more likely to be endorsed than all other options.
Criterion B: Extent to which option characteristic curves increased rapidly with changes in overall severity.
Criterion C: Does the severity region in which each option was most likely to be endorsed correspond to option weights?
Criterion D: Do options for an item span the full continuum of severity from -3 to +3?

ISSN: 1471-244X