The columns of these tables present the information listed in (a) through (d) in the same order. Blank cells in the table mean that the information was either not presented or was unclear to both reviewers in the description of the study. Minus signs (-) indicate that the condition did not hold for that study, while the check () indicates that the condition did hold.

Table 2 presents studies using vocabulary measures, while Table 3 presents studies using comprehension measures. In one study (Miller, 1941) vocabulary and comprehension measures were obtained from the same students tested at the same sitting. However, since separate analyses of vocabulary and comprehension data were made, we have reported these as separate comparisons of auding and reading performance. Where a study reported results of testing students at two or more grade levels, we recorded results by grade levels and hence the same study is cited across several grade levels. If a study reported separate analyses for different groups within a grade level, such as high ability and low ability students, we have reported these comparisons separately. Thus Tables 2 and 3 summarize 71 comparisons of auding versus reading performance from 31 research reports spanning first-grade to college students and out-of-school (mostly young) adults.

Most studies showed a fair level of design sophistication. For instance, where identical students and identical or "equivalent" materials were used, the order of presentation of the material for auding and reading was usually, although not always, counterbalanced. By "equivalent" materials we mean that the grade level or other index of difficulty, such as readability, was used to match materials presented for auding or reading. Armstrong's (1953) vocabulary study used a procedure in which students first received a printed word to read and define. If they could do the reading task it was assumed that they could have defined the word had they auded it, and hence it was counted as being in both auding and reading vocabulary. Words not read were presented in spoken form for auding and defining and counted in the auding vocabulary only.