Despite the unresolved issues in LD, students are classified and receive special education under its rubric. By examining the characteristics of students classified as LD, we may get a better sense of the nature of the condition. Large-scale investigations of LD students provide a more stable picture of LD than analyses of small samples. With small sample comparative (LD vs. non-LD) research, the most prominent weakness is the potential for biased samples; the use of accessible (i. e., school-identified) samples, rather than LD samples drawn from large populations, increases the risk that the findings will be confounded by samplespecific characteristics.