All of these statements of facts may be biased. You should always question the bias involved in obtaining and presenting data. If averages are given, ranges and standard deviations should be evaluated critically. You should learn not to be too easily impressed by statistical data. Tabulated numbers or graphs may only reflect opinions.
Many authors make much of analogies as they attempt to prove their theses.
However true the second part of the sentence may or may not be, it should not necessarily be accepted as a demonstration of the truth of the first part of the sentence. Authors generally try to show their theses in the best possible light and to discredit opposing viewpoints. When authors are so single-minded as to completely ignore opposite viewpoints, they probably are guilty of oversimplification. It may be argued, for example, that bilingual education has been shown to be beneficial for students. Each point should be analyzed as it is empirically observed, not as it is grouped with other observations.