  Effective evidence is a matter of the degree to which a person's total evidence for H depends on her opinion about E. When PE(H) and P~E(H) (or OE(H) and O~E(H)) are far apart the person's belief about E has a great effect on her belief about H: from her point of view, a great deal hangs on E's truth-value when it comes to questions about H's truth-value. A large differential in incremental evidence between E and E* tells us that learning E increases the subject's total evidence for H by a larger amount than learning E* does.  Readers may consult  Table 4 (in the supplement) for quantitative measures of effective and differential evidence.