The PGA is a 7-point scale used to measure the severity of disease at the time of the physician's evaluation of the participant. Categories are as follows: Severe = very marked plaque elevation, scaling, and/or erythema; Moderate to severe = marked plaque elevation, scaling, and/or erythema; Moderate = moderate plaque elevation, scaling, and/or erythema; Mild to moderate = intermediate between moderate and mild; Mild = slight plaque elevation, scaling, and/or erythema; Almost clear = intermediate between mild and clear; Clear = no signs of psoriasis (post-inflammatory hypopigmentation or hyperpigmentation could be present).