This paper investigates the influence of the combination of the scalability parameters in scalable video coding (SVC) schemes on the subjective visual quality. We aim at providing guidelines for an adaptation strategy of SVC that can select the optimal scalability options for resource-constrained networks. Extensive subjective tests are conducted by using two different scalable video codecs and high definition contents. The results are analyzed with respect to five dimensions, namely, codec, content, spatial resolution, temporal resolution, and frame quality.