In the coming years it will be necessary to test whether German students are meeting the requirements set by the German educational standards by means of standardized tests. This will presumably result in an immense testing effort. Adaptive testing offers an efficient alternative to conventional paper-and-pencil testing procedures and is likely to decrease testing effort significantly. Based on empirical data this study compares adaptive testing to non-adaptive testing with regard to measurement efficiency and differentiability in extreme areas of competency for different test lengths. Measurement efficiency is shown to be nearly twice as high in the adaptive framework as in the non-adaptive framework. Furthermore, the differentiability in extreme areas of competency was better for adaptive testing than for non-adaptive testing. The advantages of adaptive testing were independent of the test length. The relevance of the obtained results is discussed with respect to the forthcoming tests of educational standards in Germany