Final results are given for an investigation of the nature of the errors that arise in the course of the RAND-developed Particle-In-Cell (PIC) computation process. Among the important conclusions are that the dominant error terms bear only a casual relation to physical effects; that a pseudostress can be constructed that gives rise to the dominant errors in the momentum equation and to some of the errors in the energy equation associated with the gradients of the fluid velocity; and that the axisymmetric elements of the pseudostress suggest that the PIC equations contain errors that lead to effects associated with polar fluids. (See also RM-2628-PR, RM-3613-PR.)