Rosenthal, Robert, Heng Li and Donald B. Rubin. 1996. "Reliability of Measurement in Psychology: From Spearman-Brown to Maximal Reliability." Psychological Methods 1, No. 1: 98-107.
The authors extend the usual approach to the assessment of test or rater reliability to situations that have previously not been appropriate for the application of this standard (Spearman-Brown) approach. Specifically, the authors (a) provide an accurate overall estimate of the reliability of a test (or a panel of raters) comprising 2 or more different kinds of items (or raters), a quite common situation, and (b) provide a simple procedure for constructing the overall instrument when it comprises 2 or more kinds of items, judges, or raters, each with its own costs and its own reliabilities.