1996, will presumably be the bedrock source for estimating the parameters of a medical care risk index. However, that estimation should use variables on risk factors and insurance coverage that are available in the Current Population Survey Annual Social and Economic Supplement (CPS ASEC), so that a family’s poverty status can be compared with its medical care risk. Czajka said that he thought that any new measure, if it is intended to be a companion to the SPM, should be estimated from the same data as the SPM for at least a few years, so that users can see how the two measures work together. After that one can think about whether there is some good reason to separate them.

Factors Affecting Data Requirements

Alternative design choices have a big impact on the data requirements for a medical care economic risk measure. There are two main choices. The first is between a retrospective and a prospective measurement of risk. The first workshop session focused on prospective measures. Retrospective measures got attention in the second session. The second choice is whether resources should include assets or be limited to only income.

It is also important to distinguish between data used to develop a measure and data used to produce the measure that is disseminated to the public. Development of a measure requires data that, ideally, will support alternative measures and enable evaluation. Longitudinal data would be valuable for evaluation and validation—especially with a prospective measure. Production of a measure requires data to support only one, not multiple measures; however, timeliness, representativeness, and statistical precision become more important.

Measures of Resources

Regarding measures of resources, the CPS ASEC is the official source of estimates of income and poverty for the United States. It is also being used to construct the SPM, as it has been used to construct a number of experimental measures over the years. It includes the official measure of money income, which is what is used to estimate poverty. And it also does or will provide the measure of disposable income that goes into the SPM.

It is notable that some of the components of the SPM, and even in the CPS, have to be imputed. Not all items are collected, and taxes are the big item that has to be modeled and applied through the model or through imputation. Information on taxes is not really collected in any of these surveys.

The CPS added the measure of medical out-of-pocket expenditures and a few other components in 2010, to help support the new SPM. The



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