Do bots provide correct and adequate guidance regarding acidity: A blinded comparison rated by patients and physicians

Table 3 Readability indices used to evaluate artificial intelligence-generated patient education responses

Index	Description	Scoring/interpretation	Ref.
FRE	Based on average sentence length and syllables per word, indicates text readability	0-100 scale; higher = easier; approximately 60 = 8th grade; approximately 30s = college-level
SMOG	Estimates the grade level required to understand the text, focusing on complex polysyllabic words	Reported as United States education grade (e.g., 8th, 12th)	[11]
ARI	Uses characters per word and words per sentence to estimate grade level required	Score corresponds to United States grade level	[12]
GFI	Estimates years of formal education needed to understand text, emphasizing sentence length and complex words	Range 6-17; 6-6.9 recommended for patient education	[13]
ARC	Composite measure averaging multiple indices (e.g., SMOG, ARI, GFI, FRE) to estimate grade level	Reflects approximate United States grade level needed for comprehension	-

Each measure provides an estimate of text difficulty, expressed as either a grade level or readability score. ARC: Average reading level consensus; ARI: Automated readability index; FRE: Flesch reading ease; GFI: Gunning fog index; SMOG: Simple Measure of Gobbledygook.