Table 1.

Examples of CI results: Participant Think Aloud (TA) and Interviewer Probing (IP).

Sample Omitted Items	Reason for Omission
I felt the presence of evil around me. (Religious/Persecutory Delusion)	Responses from participant think aloud (TA) and interviewer probing (IP) indicated that participants interpreted the item as meaning there were ‘bad people’ (a bad element) around them, which led to a higher base rate of endorsement than was expected.
I thought people might be able to read my mind. (Thought Broadcasting/Delusions of Control)	In response to TA & IP, participants provided examples of parents’ knowing what they were thinking and anticipating their next move. This led to a higher base rate of endorsement than was expected.
People said I did not show emotions. (Affective Flattening)	Participants stated that people did not say this.
I spent time with friends after work or school. (Social Functioning)	TA & IP responses, as well as responses to other social functioning items, indicated that negative endorsement of the item (i.e., Never) often reflected the inability to engage with friends due to other commitments (e.g., do homework, babysit siblings), rather than poor social functioning.
Sample Revised Items	Reason for Revision
Original item: I thought people were watching me. Revised item: People were plotting against me. (Paranoid/Persecutory Delusions)	Participant TA & IP responses indicated a high base rate of endorsement, especially among adolescents. They thought people were watching them all the time at school.
Original Item: I felt anxious. Revised Item: I had anxiety. (Anxiety)	Anxious in the context of “I felt anxious” was defined as excited or eager (e.g., “I was anxious to go to the fair”) by participants, particularly those in the South. The noun form, however, did not have the same additional connotation; therefore, the item was revised to use the noun form of anxiety.
Original Item: I thought I might be God’s personal messenger on Earth. Revised Item: I am the only person who can do God’s work on Earth. (Religious Delusions)	The original item produced a high base rate of endorsement among devoutly religious participants. The revised item is distinct from the notion that all people are God’s children or messengers.
Original Item: I thought people were planning to hurt me. Revised Item: I thought people were planning to physically hurt me. (Paranoid/Persecutory Delusions)	Participant interpretations of the original item included emotional harm, which had a high base rate (i.e., hurting feelings). The revised item narrowed the item’s focus to physical harm.
Original item: I thought I had special powers. Revised item: I thought I had superhuman powers. (Grandiose Delusions)	Participant TA & IP responses indicated a high base rate of endorsement due to personal qualities (e.g., the gift of gab, good listener). The revised item clarifies the item’s intent of assessing grandiosity.
Original instructions: Now I’m going to ask you about things you thought you might have seen while you were fully awake and it was light. Revised instructions: Now I’m going to ask you about things you might have seen while you were fully awake and there was enough light to see clearly. (Visual Hallucinations)	Participant TA & IP responses indicated high endorsement due to appearance of shadows due to dim light. The revised instructions clarify that visual hallucinations were present when enough light was present to see clearly (i.e., eliminate shadows).
Sample Retained Items	Reason for Retaining Item
I thought I deserved to be punished. (Persecutory Delusion or Guilt)	Easily understood in early rounds of CI & central to Persecutory Delusions
My thoughts were being controlled. (Delusions of Control)	Easily understood in early rounds of CI & central to Delusions of Control
I felt like someone was touching me, but no one was there. (Tactile Hallucinations)	Easily understood in early rounds of CI* & central to Somatic Delusions *This is especially important given the contingent nature of the question.
I had difficulty feeling emotions. (Affective Flattening)	Easily understood in early rounds of CI & central to Affective Flattening