The study reports the use of lambda, a measure of sequential dependency developed by Lathrop (1964) in connection with electrodermal activity. Thirteen female subjects, ranging in age from 19 to 53, participated in a simple repeat-stimulus habituation experiment: GSR data in percent-change and lambda were compared. A high, positive correlation was obtained. Consequently, the use of lambda is advocated because it shows both initial value and sequential dependency and meets the criteria for analysis based on the probability of statistics such as t and F.