To the Editor.— Double-blind studies have so often failed to add reliability to assays of therapeutic effectiveness that wits are now wont to say "it's the blind leading the blind." Though the procedure has merit in some situations, it will not prevent the poor observer from making false-positive or false-negative decisions. Rascals, on the other hand, can see through any blind scheme. At times the double-blind format may seriously impair clinical evaluation by locking the investigator into fixed regimens wherein dosage cannot be adjusted to individual needs. With drugs that produce prominent reactions such as erythema, the only way to avoid breaking the code is to keep the eyes shut tightly. How in the world can one perform a double-blind study of retinoic acid vs a placebo in acne when erythema and peeling will immediately identify the active agent or of a cytostatic agent in psoriasis when clearing is preceded