Table 3.

The questionnaire

Preamble
PRE.1	A. Please estimate, during an average week of your practice, how many Drug–Drug Interaction alerts you receive from [name of CPOE]? _____ (Please provide a numeric estimate)
PRE.2	B. Please estimate, of the Drug–Drug Interaction alerts you receive, what per cent do you read thoroughly? _____ %
PRE.3	C. Please estimate, of the Drug–Drug Interaction alerts you read, what per cent do you find relevant? _____ %
PRE.4	D. Please estimate, of the Drug–Drug Interaction alerts you find relevant, what per cent change your prescribing decisions? _____ %
Section 1 of 5 Please respond to the following statements based on your experience using [name of CPOE] at [name of institution] (Scale: Strongly Disagree, Disagree, Agree, Strongly Agree, and Does not apply)
PE.1	1. Drug–Drug Interaction (DDI) alerts are useful in helping me care for my patients.
PE.2	2. DDI alerts are relevant to the individual patients for which they appear.
PE.3	3. DDI alerts capture all drug interaction instances for my patients.
PE.4	4. DDI alerts I receive are clinically important.
PE.5	5. DDI alerts help me better understand which drugs should not be used at the same time.
PE.6	6. DDI alerts help me improve the monitoring for and management of DDIs for my patients.
PE.7	7. DDI alerts help me reduce professional risk by preventing potential adverse events in my patients.
Section 2 of 5
EE.1/EU1*	8. I find Drug–Drug Interaction (DDI) alerts easy to understand.
EE.2/EU2*	9. The system makes it easy to respond to DDI alerts.
EE.3	10. Reading and responding to DDI alerts takes too much time.
EE.4	11. I repeatedly receive DDI alerts to which I have already responded.
EE.5	12. Reading and responding to DDI alerts interferes with my workflow.
SI.1	13. I read and respond to Drug–Drug Interaction (DDI) alerts because my colleagues read and respond to them.
SI.2	14. My supervisor (eg, attending physicians, nurse managers) encourages me to read and respond to DDI alerts.
SI.3	15. Reading and responding to DDI alerts helps to improve my professional image.
Section 3 of 5
FC.1	16. I received adequate training on how to read and respond to Drug–Drug Interaction (DDI) alerts.
FC.2	17. I have adequate clinical knowledge to understand DDI alerts.
FC.3	18. The system provides adequate explanations of clinical relevance for DDI alerts.
FC.4	19. The system provides adequate management alternatives for DDI alerts.
FC.5	20. If I have questions about DDI alerts, I always have someone to consult with.
Section 4 of 5
PF	21. During order entry, I receive too many Drug–Drug Interaction (DDI) alerts that I must read and respond to.
Section 5 of 5 Please respond to the following statements based on your experience using [name of CPOE] at [name of institution] (Scale: Never, Rarely, Less than half the time, About half the time, More than half the time, Always, and Does not apply)
UB.1	22. I thoroughly read the Drug–Drug Interaction (DDI) alerts that I receive.
UB.2	23. I provide reasons for DDI alerts that I decide to override.
UB.3	24. DDI alerts presented to me during order entry change my prescribing decisions.
Open-ended closing
Please provide any additional comments you have regarding Drug–Drug Interaction alerts you receive from [name of CPOE]. Thank you for your time.

^*EE.1 and EE.2 should be treated as a standalone construct, ‘perceived ease of use’ (EU), according to field validation results; see the Validation results section for more detail.