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. Author manuscript; available in PMC: 2021 Dec 15.
Published in final edited form as: J Neurol Sci. 2020 Nov 1;419:117205. doi: 10.1016/j.jns.2020.117205

Table 2.

Clinimetric properties of the AM item for various exclusions

Item to Total Correlation Cronbach’s Alpha if Item Omitted IRT Discrimination MAD
SITE RATINGS
Original Sample (n = 208 patients) 0.011 Increase 0.09 N/A
Sufficient Duration and Severity (n = 145 patients) 0.153 Decrease 0.341 N/A
Sites with Greater Than 10 Patients (n = 137 patients) 0.182 Decrease 0.409 N/A
Reverse Scoring Omitted (n = 127 patients) 0.251 Decrease 0.467 N/A
VIDEO RATINGS
Video Ratings with 5 Raters (n = 80 patients, 400 ratings) 0.231 No Change 0.718 0.91
Sufficient Duration and Severity (n = 60 patients, 300 ratings) 0.405 Decrease 1.163 0.75
Reverse Scoring Omitted (n = 60 patients, 273 ratings) 0.444 Decrease 1.29 0.68

Clinimetric properties of the AM item, before and after excluding patienls with insufficient severity and duration of AM trial and raters using reverse scoring (IRT = item response theory; MAD = mean absolute difference).