Calendarization: A generic term for benchmarking.

Calendar plot: A method of describing compliance for individual patients in a clinical trial, where the number of tablets taken per day are set in a calendar-like form (see Figure 12). See also chronology plot. [Statistics in Medicine, 1997, 16, 1653–64.]

Calibration: A procedure that enables a series of easily obtainable but possibly less precise measurements to be used in place of more expensive or more-difficult-to-obtain measurements of some quantity of interest. Suppose, for example, that there is a well-established, accurate method of measuring the concentration of a given chemical compound, but that it is too expensive and/or cumbersome for routine use. A cheap and easy-to-apply alternative is developed that is, however, known to be imprecise and possibly subject to bias. By using both methods over a range of concentrations of the compound, and applying regression analysis to the values from the cheap method and the corresponding values from the accurate method, a calibration curve can be constructed that may, in future applications, be used to read off estimates of the required concentration from the values given by the less involved, inaccurate method. [International Statistical Institute, 1991, 59, 309–36.]

Calibration curve: See calibration. California score: A score used in studies of sudden infant death syndrome that gives the number from eight adverse conditions present for a given infant. The events include fewer than 11 antenatal visits, male sex, birthweight under 3000 g and mother under 25 years old.