Table 3.

Validity and Reliability of Survey Instruments used to measure Patient Level Factors

Variable	Instrument	Construct and General Information	Reliability	Validity	Study
Anxiety	GAD-7	7-item questionnaire Identifies likely cases of generalised anxiety disorder. Items are rated for past 2 weeks on 4-point scale for the frequency of anxiety symptoms. Scores can range from 0-21, with cut points at 5, 10, &15 representing mild, moderate, and severe levels of anxiety.	Cronbach’s α= 0.92	r= 0.72-0.74 correlated with the Beck Anxiety Inventory, anxiety subscale of the Symptom Checklist-90 Can be used among the general population	Spitzer et al., 2006
Depression	PHQ-8	8-item questionnaire identifies likely cases of depressive disorder(s). Items are rated for the past 2 weeks on a 4-point scale for the frequency of depression symptoms. Scores can range from 0-24, with <10 = negative for depression, ≥10 = major depression, and 20+ = indicates severe major depression.	Cronbach’s α= 0.86- 0.89	AUC= 0.95 in discriminating between patients with and without major depression Can be used among the general population	Kroenke et al., 2001; Kroenke et al., 2009
Pain Catastrophizing	PCS	13 item pain questionnaire which measures 3 domains (magnification, rumination, & helplessness) about pain. Items are rated on a 5-point scale with anchors being “not at all” and “all the time”. Scores can range from 0-52, with a score of 30 representing clinically relevant level of catastrophizing.	Cronbach’s α= 0.95	r= 0.80, p<0.001 when compared to the Fear of Pain Questionnaire Can be used in the general population	Osman et al., 2000; Sullivan, Bishop, & Pivik, 1995
Anticipatory Pain Intensity	NRS	Self-report on vertical 0-10 Numeric Rating Scale with 0.5 increments. The subject is asked how much pain they expect to have during the dressing change.	The NRS was not developed to assess Anticipatory Pain, thus there is no validity or reliability data for this indication. However, Woo et al. (2008) & Woo (2015) used the 11-point NRS (0-10) to assess anticipatory pain associated with dressing change procedures, and found the NRS is the best method for accurately and reliably determining the subject’s real-time pain experience and expectations. *The 0-10 NRS has been assessed for Reliability and Validity for Pain Intensity, this information can be found with the “Pain Intensity” variable.