Abstract
Although most studies of reading behavior have little scientific value if their conclusions have to be restricted to the specific materials that were used in the experiment, reading researchers have seldom used designs that would enable them to generalize beyond the particular letters, words, sentences, and so on they chanced to use. Data from an experiment by Carver are used to show that it is therefore likely that many experiments could not be replicated if different samples of materials were drawn. Evidence is also given that reading speed, if measured in a fine-grained unit such as letters per second, does not increase as passages become more difficult, but is a constant across a range that extends from first-grade texts to technical prose.