This study was designed to ascertain the intrasubject variability across mu
ltiple recording sessions-most often disregarded in reporting group mean da
ta or unavailable because of single sample experimental designs. Intrasubje
ct variability was assessed within and across several experimental sessions
from measures of speaking fundamental frequency, vocal intensity, and read
ing rate. Three age groups of men and women-young, middle-aged, and elderly
-repeated the vowel /a/, read a standard passage, and spoke extemporaneousl
y during each experimental session. Statistical analyses were performed to
assess each speaker's variability from his or her own mean, and that which
consistently varied for any one speaking sample type, both within or across
days. Results indicated that intrasubject variability was minimal, with ap
proximately 4% of the data exhibiting significant variation across experime
ntal sessions.