Constraints on the dark energy (w₀, w_a) parameters measured from: simulations that include only Gaussian shape noise and Gaussian photo-z uncertainties (blue) and simulations that include Gaussian shape noise, Gaussian photo-z uncertainties, and a 5% level of catastrophic photo-z errors (outliers) that result from the Lyman-α line in the galaxy SED being misidentified as the Balmer and D4000 break features (red). From left to right, we plot the constraints derived from tomographic analyses of the full 3 × 2 pt signal using a single redshift bin, five equipopulated bins, and ten equipopulated bins.