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CALMAR 2: A NEW VERSION OF THE CALMAR CALIBRATION ADJUSTMENT PROGRAM Olivier Sautory1 ABSTRACT Calmar 2 is the new version of the Calmar calibration adjustment program. It contains two major developments. When survey data are collected at different levels (e.g., households and individuals), simultaneous calibration of the samples helps maintain consistency in the statistics produced from the samples. Where there is total non-response, generalized calibration makes it possible to rewrite the calibration equations with two sets of variables: the actual calibration variables and the non-response explanatory variables. This corrects for non-response even when the variables that explain it are unknown for the sample non-respondents. KEYWORDS: Calibration; Generalized Calibration; Non-Response; Simultaneous Calibration. 1. THE CALMAR MACROS Background Calmar is a SAS macro program that implements the calibration methods developed by Deville and Särndal (1992). The program adjusts samples, through reweighting of individuals, using auxiliary information available from a number of variables referred to as calibration variables. The weights produced by this method are used to calibrate the sample on known population totals in the case of quantitative variables and on known category frequencies in the case of qualitative variables. Calmar is an acronym for CALibration on MARgins, an adjustment technique which adjusts the margins (estimated from a sample) of a contingency table of two or more qualitative variables to the known population margins. However, the program is more general than mere “calibration on margins,” since it also calibrates on the totals of quantitative variables. Calmar was developed in 1990 at France’s Institut National de la Statistique et des Études Économiques (INSEE), where it is used regularly to adjust survey data. It is also used by many other statistics agencies in France and other countries. The new version, Calmar 2, developed in 2003, offers the user new resources for performing calibrations and implements the generalized calibration method of handling non-response proposed by Deville (1998). Calmar can be downloaded from INSEE’s Web site (www.insee.fr), and Calmar 2 will also be available on the site sometime in 2006. 1.2 Calmar’s calibration methods It is worth restating the principle underlying the calibration methods implemented by Calmar (see also Deville et al., 1993). Consider a population U of individuals, from which a probabilistic sample s has been selected. Let Y be a variable of interest, for which we want to estimate the total in the population : ∑∈=UkkyY . 1 Olivier Sautory, Cepe-Insee, 3 avenue Pierre Larousse, 92245 Malakoff Cedex, France, sautory@ensae.fr. This text has been first published in the Statistics Canada International Symposium Series - Proceedings, 2003.