Treatment outcome in epilepsy is too often a vague, ill-defined subjec
tive measure. Based on a proposal of Shoffer and Temkin (1987) of ''ti
me to kth seizure'' as a measure of seizure frequency, we devised the
formula: % improvement = 100 - [time to X seizure (i) x 100]/[time to
X seizure (f)]. This formula provides an objective measure of treatm
ent outcome and should prove useful in clinical settings and research.
We offer examples of practical applications of the formula.