Recently, the H.264/AVC standard has been extended to incorporate Scalable Video Coding (SVC). SVC offers the advantage of scalable (layered) coding, but has the disadvantage of a highly increased computational complexity at the encoder side when dealing with spatial scalability. To restrict the increase in required processing power, fast mode decision models for spatial enhancement layers have been proposed in literature. We propose a novel generic fast mode decision model for spatial enhancement layers for both P and B frames based on both the quantization of the enhancement layer and the correlation between the macroblock type in the enhancement layer and the co-located macroblock in the reference layer. In this paper, an evaluation of the proposed model and comparison with a state-of-the-art model is given. Results show that the proposed technique performs exceptionally well for spatial scalability. For both dyadic and non-dyadic spatial scalability, we achieve an average time saving of 75%, while only a slight bit rate increase of 2.23% and a minor PSNR decrease of 0.46 dB are measured. Compared with state of the art techniques, we further halve the complexity while having comparable rate-distortion results.