Abstract： We analyze the doubly differential electron distribution in atomic above-threshold ionization by a linearly-polarized short-laser pulse. We generalize the one-dimensional (1D) simple man’s model (SMM) of Arbó et al., to a three dimensional (3D) description by using the saddle-point approximation (SPA). We prove that the factorization of the photoelectron spectrum in terms of intracycle and intercycle interference patterns can be ex...