The residual surface resistance of a number of films of YBa2Cu3O7−x, prepared by off-axis sputtering onto MgO substrates, has been measured using a parallel-plate resonator technique. Deposition conditions were kept constant, apart from the substrate temperature. There is no correlation between surface resistance and other important microscopic parameters, such as Tc and c-axis lattice parameter. There is, however, a trend to higher Rs with increasing volume fraction of in-plane misoriented material, although the correlation is not perfect. Furthermore, we have found that most of the misoriented material is localized at the film substrate interface and, therefore, is probably not responsible for most of the RF losses. The data suggest that at higher deposition temperatures, there is an increasing tendency for 45° misoriented material to appear in the films, and a significant fraction of this material may be present closer to the free film surface. Scanning Tunneling Microscopy (STM) qualitatively supports this conclusion.