Table 2.

Reliability of NADL.

	Cronbach's alpha	Test–retest reliability	Inter-rater reliability
Interview with patients	0.5	0.69	0.82
Interview with caregiver	0.62	0.98	1
Informal total	0.64	0.86	0.94
Formal total	0.73	0.86	0.87
Numerosity comparison	0.8	0.51	0.84
Number line	0.73	0.50	0.60
Digit comparison	0.71	0.32	0.9
Reading number aloud	0.37	0.20	0.68
Writing numbers on dictation	0.19	0.24	0.2
Mental addition	0.7	0.28	0.58
Mental subtraction	0.5	0.44	0.95
Mental multiplication	0.61	0.72	0.92
Written rules	0.59	0.38	0.55
Written addition	0.65	0.68	0.81
Written multiplication	0.63	0.46	0.62
Written operations—addition	0.6	0.60	0.66
Written operations—subtraction	0.71	0.50	0.83
Written operations—multiplication	0.6	0.38	0.55
Total number comprehension	0.43	0.34	0.78
Total reading and writing Arabic numerals	0.39	0.39	0.62
Total mental calculation	0.58	0.76	0.93
Total rules and principles	0.78	0.88	0.92
Total written calculation	0.74	0.47	0.68

The Table reports reliability scores for NADL.